Bi2MoO6 Microsphere with Double-Polyaniline Layers toward Ultrastable Lithium Energy Storage by Reinforced Structure

Article abstract of DOI:10.1021/acs.inorgchem.9b00627

Given its competitive theoretical capacity, Bi₂MoO₆ is deemed as a promising anode material for the realization of efficient Li storage. Considering the severe capacity attenuation caused by the lithiation-induced expansion, it is essential to introduce effective modification. Remarkably, in this work, Bi₂MoO₆ microsphere with double-layered spherical shells are successfully prepared, and the polyaniline are coated on both inner and outer surfaces of double-layered spherical shells, working as buffer layers to strain the volume expansion during electrochemical cycling. Inspiringly, when utilized as anode in LIBs, the specific capacity of Bi₂MoO₆@PANI is maintained at 656.3 mAh g^-1 after 200 cycles at 100 mA g^-1, corresponding to a high capacity of 82%. However, the counterpart of individual Bi₂MoO₆ is only 36%. This result confirms that the polyaniline layer can dramatically promote stable cycling performances. Supported by in situ EIS and ex situ technologies followed by detailed analysis, the enhanced pseudocapacitance-dominated contributions and electron/ion transfer rate, benefiting from the combination with polyaniline, are further proved. This work confirms the significant effect of polyaniline on the ultrastable energy storage, further providing an in-depth sight on the impacts of polyaniline coating to the electrical conductivity as well as the resistances of electron/ion transport.

Full text of DOI:10.1021/acs.inorgchem.9b00627

Article
Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX
pubs.acs.org/IC
Bi MoO Microsphere with Double-Polyaniline Layers toward
2
6
Ultrastable Lithium Energy Storage by Reinforced Structure
Yang Zhang, Ganggang Zhao, Peng Ge, Tianjing Wu, Lin Li, Peng Cai, Cheng Liu, Guoqiang Zou,*
Hongshuai Hou, and Xiaobo Ji
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
*
S Supporting Information
ABSTRACT: Given its competitive theoretical capacity, Bi MoO is
2
6
deemed as a promising anode material for the realization of efficient Li
storage. Considering the severe capacity attenuation caused by the
lithiation-induced expansion, it is essential to introduce effective
modification. Remarkably, in this work, Bi MoO microsphere with
2
6
double-layered spherical shells are successfully prepared, and the
polyaniline are coated on both inner and outer surfaces of double-layered
spherical shells, working as buffer layers to strain the volume expansion
during electrochemical cycling. Inspiringly, when utilized as anode in LIBs,
−
1
the specific capacity of Bi MoO @PANI is maintained at 656.3 mAh g
2
6
−
1
after 200 cycles at 100 mA g , corresponding to a high capacity of 82%.
However, the counterpart of individual Bi MoO is only 36%. This result
2
6
confirms that the polyaniline layer can dramatically promote stable cycling
performances. Supported by in situ EIS and ex situ technologies followed
by detailed analysis, the enhanced pseudocapacitance-dominated contributions and electron/ion transfer rate, benefiting from
the combination with polyaniline, are further proved. This work confirms the significant effect of polyaniline on the ultrastable
energy storage, further providing an in-depth sight on the impacts of polyaniline coating to the electrical conductivity as well as
the resistances of electron/ion transport.
1
. INTRODUCTION
nanosheets with self-adaptive oxygen vacancies displayed a
19
superior high-rate cyclic stability. 3D hierarchical porous
Triggered by the limited theoretical specific capacity (372 mAh
20
−
1
Bi MoO microspheres showed a high Coulombic efficiency.
2 6
g ) of commercial graphite anode, the ever-growing demands
have been made for alternative electrode materials for Lithium-
ion batteries (LIBs) with higher energy density, better safety
Bi MoO /rGO composites delivered higher capacity than that
2
6
21
of pure Bi MoO . It is noted that many effective strategies
2
6
1
−3
were employed to modify the Bi MoO anode materials above
2 6
features and enhanced rate performances. In terms of large-
scale fabrication and high theoretical specific capacity, a
number of metal oxides have been paid close attention as
potential anode materials for LIBs such as MoO , Fe O ,
SnO2, and Co O4 in recent years. Nevertheless, the
commercial applications of most metal oxides were seriously
hindered by their low conductivity and severe capacity fading
caused by volume expansion and further structural pulveriza-
tion during the repeated lithiation/delithiation processes. It
is well-defined that multicomponent metal oxides normally
show the enhanced electrochemical performances than that of
single-component metal oxides due to their rich chemical
component and synergistic reactions between multiple metal
to circumvent the obstacles of capacity fading, thus leading to
high capacity and outstanding cyclic durability.
4
5
As established previously, various approaches have been
developed to improve the structural stability of electrode
materials, further promoting electrochemical performances.
Among those strategies, 3D hollow structure was supported as
an efficient synthetic solution to the alleviation of volume
3
3
4
6
7
3
2
2,23
8
,9
expansion thus realizing stable cycling performances.
Considering the destruction of the structure while removing
the template, the hollow structure, obtained by hard-
templating approach, exhibited subdued electrochemical
performances. Therefore, it is meaningful to develop
template-free methods to prepare hollow structure. Further-
more, the combination with active carbon was proved to
effectively reduce capacity attenuation and enhance electronic
1
0
species.
Particularly, Bi MoO , a layered structure consisted of
2
6
2
+
[
[
Bi O ]
MoO ] ,
and slabs interleaved by double slabs of
2
2
24,25
4
+
11,12
conductivity of the electrode materials.
Remarkably, as a
has been widely studied as a photocatalyst for
1
4
3−17
conductive polymer, polyaniline (PANI) can be produced
its excellent photoelectric properties
and as an electrode
materials for energy storage devices, such as LIBs, on account
−
1
of its high theoretical specific capacity (791 mAh g ) and low
Received: March 4, 2019
18
desertion voltage (<1.0 V). For example, ultrathin Bi MoO
2
6
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
through the oxidative polymerization of aniline monomers.
Moreover, the combination of electrode materials with PANI
can stabilize the electrode structure, prevent electrolyte
erosion, and boost ion/electron diffusion, hence ameliorating
26−30
the electrochemical properties.
It was found that the
introduction of PANI coating layers could address almost all of
the key challenges for Bi MoO electrode materials. First, it
2
6
could enhance the electrical conductivity of Bi MoO , thereby
2
6
accelerating the electro/ion transport. Next, the PANI layers
could buffer the volume expansion upon cycling thus
preventing the loss of electrical contact of the active materials
by holding the structural integrity.
Additionally, the kind of dominant electrochemical behav-
iors would have significant impacts on the electrochemical
performances. Previous reports have clearly shown us that the
pseudocapacitance-dominated behavior could yield enhanced
3
1
charge/discharge progress and superior cyclic stability.
Notably, the former researches confirmed that the conductive
polymer with electronic activity could realize the improvement
32
of capacitive contribution. Under the circumstances, an
effective and scalable synthesis approach has been introduced
for fabrication of Bi MoO @PANI composites for LIBs.
2
6
Herein, Bi MoO @PANI microspheres were prepared by
2
6
the oxidative polymerization of aniline on both exterior and
interior surfaces of individual Bi MoO6 double-layered
2
spherical shells. Profiting from this advantage, the acquired
Bi MoO @PANI exhibited superior cyclic stability compared
2
6
with pristine Bi MoO when they were utilized as the anode
2
6
Figure 1. (a) Schematic diagram of lithium shuttling. (b) XRD
materials for LIBs. A high reversible specific capacity of 656.3
patterns; (c) TG curves; (d) FT-IR; (e) Raman spectra of Bi MoO
−
1
−1
2
6
mAh g was attained at a current density of 100 mA g even
after 200 cycles with a remarkable retention of 82%, while pure
and Bi MoO @PANI.
2
6
−
1
Bi MoO only delivered 288.7 mAh g with a poor retention
2
6
pattern, which was ascribed to the high peak intensity of
Bi MoO , revealing that the crystalline behavior of the
of 36%. This work demonstrates that the combination with
PANI is an effective perspective to improve the electrical
conductivity and cyclic stability of the ternary metal oxides
anode for LIBs.
2
6
Bi MoO was not obviously impacted by the low content of
2
6
PANI. According to the Scherrer equation (Dhkl = Kλ/β cos θ,
K = 0.89, λ = 0.154 nm, β is the full width at half-maximum
34
(
fwhm)), and the Bragg equation (2d sin θ = nλ), crystalline
2
. RESULTS AND DISCUSSION
.1. Structure and Morphological Characterization.
As exhibited in Figure 1a, confining the pure Bi MoO in
grains size, and interplanar spacing can be estimated,
respectively, with the results listed in Table 1. In clear
2
2
6
PANI conductive layer and realizing interface modification
could promote the interfacial charge transferring and prevent
the electrodes from the electrolyte erosion, and the crystal
structure of Bi MoO was concurrently shown in the inset. The
crystalline nature and purity of the as-prepared samples were
examined by X-ray diffraction (XRD) and the results were
plotted in Figure 1b. According to the patterns, the peaks
located at 10.93, 23.52, 28.26, 32.53, 46.74, 55.59, and
Table 1. Structural Parameters of Bi MoO and Bi MoO @
PANI Determined from XRD Rietveld Refinement
2
6
2
6
2θ (deg)
β (rad)
Dhkl (nm) d(131) (nm)
2
6
2
Bi MoO6
28.26
28.24
0.003124
0.004328
45.24
32.65
0.315
0.316
Bi MoO @PANI
2
6
contrast, the thickness in vertical direction of (1 3 1) was
5
8.48°were noticed, corresponding to (0 2 0), (1 1 1), (1 3 1),
calculated to ∼45.24 nm of pure Bi MoO and ∼32.65 nm of
2 6
2
6
(
2 0 0), (2 0 2), (1 3 3), and (2 6 2) lattice planes, respectively,
Bi MoO @PANI, and the nanosize particles were of
reflecting all the typical sharp diffraction peaks in the XRD
significance for increased surface area of electrode, further
releasing more active sites for lithium storage. Furthermore,
the slightly larger (1 3 1) d-spacing of Bi MoO @PANI may
patterns of the pristine Bi MoO were readily matched with
2
6
the standard pattern of orthorhombic Bi MoO6 (Powder
2
2
6
Diffraction File (PDF) no. 21-0102, Joint Committee on
Powder Diffraction Standards (JCPDS), 2007). No extra
diffraction peak was observed, indicating the high purity of the
as-obtained product. As for the Bi MoO @PANI composite, it
be ascribed to the insertion of PANI into the interlaminations
of pure Bi MoO , and the larger d-spacing can accelerate the
2
6
3
5
fast Li-ion transfer during the charge/discharge processes.
To further calculate the content of PANI in Bi MoO @
2
6
2
6
has a XRD pattern similar to that of pure Bi MoO , with the
PANI composite, thermogravimetric (TG) analysis was carried
2
6
−
1
most strong peaks observed at 2θ of 28.24°, but the intensities
of those characteristic peaks were weaker than those of pure
Bi MoO (∼1:5), illuminating the lower crystallinity and the
out at a heating rate of 10 °C min in air atmosphere (Figure
1c). The hybrid Bi MoO @PANI composite exhibited a three-
2
6
contacts weight-loss range, which included 1.84% weight loss
before 180 °C, 3.65% weight loss between 180 and 400 °C,
and 1.57% weight loss after 400 °C, corresponding to the loss
2
6
33
decreased crystallite dimension of different crystal faces.
Meanwhile, no obvious peak of PANI was detected in the
B
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
of surface absorbed moisture, the degradation of polymer
36
chain, and the decomposition and oxidation of PANI.
Compared to the TG curve of pristine Bi MoO , the weight
2
6
content of PANI was approximately calculated to be about
.22%. FT-IR analysis and Raman spectra were performed to
5
further investigate the detailed crystal structure, chemical
composition and the existence of PANI. FT-IR spectra were
displayed in Figure 1d. As for the pristine Bi MoO , the
2
6
characteristic bands located at 566.04, 740.19, and 842.56
−
1
cm were related to the bending vibration of the MoO6
octahedron, the asymmetric stretching mode of MoO , and the
6
symmetric and asymmetric vibration modes (Mo−O stretch-
6
−
ing) of the corner sharing (MoO ) octahedron, respec-
6
3
7
tively, which still remained in the case of Bi MoO @PANI
composites. Besides, the band located at 1648.41 cm can be
2
6
−
1
attributed to the CC stretching vibration modes of
3
8
quinonoid, whereas the other band vibration of PANI
cannot be obviously observed, which might be caused by the
insertion of PANI into the interlaminations of Bi MoO and
2
6
highly scattered in the composites or the low content of PANI.
The Raman spectra were shown in Figure 1e: The bands
located at 138, 191, 283, 324, 352, and 403 cm− were ascribed
to the bent, wagged, and twisted modes of the Mo−O bond,
and the bands at 714, 797, and 847 cm− were due to the
stretches of Mo−O band. All bands can be indexed to γ-
1
1
2
1,39−41
Bi MoO .
As for the Raman spectra of Bi MoO @
2
6
2 6
PANI, all characteristic bands of PANI, mainly in the spectral
−
1
−1
ranges of 400−700 cm and 1000−1800 cm , were observed,
Figure 2. XPS spectra of Bi MoO @PANI: (a) full XPS spectra; high-
resolution spectra of (b) Bi 4f, (c) Mo 3d, (d) C 1s, and (e) N 1s.
2
6
which were related to characteristic fundamental vibrations of
+
the functional groups, such as in-plane C−H bending, C−N
stretching, CN stretching of quinoid, C−H deformation, C−
N−C torsion, and C−C stretching of benzoid and amine
deformation, consistent with the Raman analysis of other
resolution spectra of N 1s (Figure 2e) were assigned to N−,
+
−
NH−, and N , which were related to the quinonoid imine,
the benzenoid amine and the nitrogen cationic radical of
PANI, respectively.
42
46,47
composites successfully coated with PANI. Compared to that
of pure Bi MoO , the Raman spectra of the Bi MoO @PANI
All the XPS analysis effectively
2
6
2
6
manifested the existence of PANI.
composites exhibited distinguishable differences, including a
drastic decrease in intensity, a slight shift in position, and an
extension in width of the Mo−O stretching Raman bands,
testifying that the degree of crystallinity was weakened by the
PANI, in line with the results of XRD and the lower
crystallinity was in favor of enhanced capacitive behaviors.
These results above revealed that the surface chemical
condition of the Bi MoO /PANI composites has been changed
With regard to microstructure of the samples and the effect
of PANI upon the structure of pure Bi MoO , the detailed
morphologies and crystal structures were revealed in Figure 3.
2
6
As shown by the SEM images in Figure 3a−c, the Bi MoO
2
6
microspheres with an average diameter of ∼1.5 μm were
distributed, revealing the structure of double-layered spherical
shells that can be evidently found in high-magnification SEM
image. As for the SEM images of Bi MoO @PANI composites
2
6
2
6
on account of the coupled effect between Bi MoO and PANI
(Figure 3d−f), it was clear that the amount of PANI had a
2
6
14
in the Bi MoO @PANI samples.
significant effect on the morphology of the pure Bi MoO .
2
6
2
6
The X-ray photoelectron spectroscopy (XPS) was displayed
to investigate the elemental composition and the surface
chemical valence states, and the detailed spectra were found in
Figures 2 and S1. It was clear that the major peaks of Bi 4f, Mo
First, it is intuitive that those spheres were more robust.
Besides this and most important was that both the exterior and
interior surfaces of pure Bi MoO microspheres were coated
2
6
with PANI owing to the free shuttle of aniline small molecules,
resulting in the formation of double-PANI layers and thus
preventing the structure from fragmentation during cycling,
which could be directly demonstrated from the inset of Figures
3f and S2. To ensure elements distribution in Bi MoO @PANI
3
d, and O 1d were delivered at about 230, 160, and 531 eV in
the survey spectra of Bi MoO @PANI (Figure 2a) and
2
6
another two stronger peaks were located at about 285 and
98 eV, corresponding to the C 1s and N 1s, respectively.
From the high-resolution spectra of Bi 4f in Figure 2b, the
3
2
6
composites, energy-dispersive spectroscopy (EDS) element
mapping and analysis was investigated and the results were
showed in Figure 3g,h. The elemental mapping in the selected
area of the composites clearly reflected that the existence of C,
N, Bi, Mo, and O elements. Moreover, the mass/atomic ratios
were listed as a table, further attesting the target product
Bi MoO @PANI was prepared. As displayed in Figure 4a,b,
6
+
characteristic peaks of Bi for Bi 4f and Bi 4f5/2 are observed
7
/2
4
3
at 158.8 and 164.1 eV, respectively. The core smooth peaks
of Mo 3d at 232.1 and 235.2 eV in Figure 2c were related to
Mo 3d and Mo 3d3/2 of Mo6 without an other chemical
state. In addition, the high-resolution spectra of C 1s (Figure
d) revealed four peaks at 284.6, 285.8, 287.6, and 288.6 eV,
+
5
/2
4
4
2
2
6
corresponding to C−C/C−H, C−N/CN, C−O, and CO
the hollow structure of pure Bi MoO microspheres were
obviously exhibited in TEM images because of the clear
contrast between the dark margin and the gray scale, and the
2 6
45
groups, respectively. The three peaks with binding energies
centered at 396.0, 397.8, and 399.7 eV indicated in the high-
C
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure 3. SEM images of (a−c) Bi MoO , (d−f) Bi MoO @PANI; (g) the mapping images and (h) EDS of Bi MoO @PANI.
2
6
2
6
2
6
Figure 4. TEM images of (a−c) Bi MoO and (d−f) Bi MoO @PANI. (g) Selected area diffraction pattern (SAED) and (h) mapping images of C,
2
6
2
6
N, Bi, Mo, and O elements.
D
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Scheme 1. Schematic Diagram of Bi MoO @PANI
2
6
disordered nanosheets were observed in the surface, which was
consistent with the SEM analysis.
pure Bi MoO spheres and Bi MoO @PANI composites were
2
6
2
6
preliminarily investigated using cyclic voltammetry (CV).
Figure 5a,b displayed the CV curves of Bi MoO and
From the high-resolution TEM (HRTEM) (Figure 4c), the
obvious lattice fringes were observed at about 0.277 nm,
corresponding to the plane (2 0 0) of Bi MoO (PDF no. 21−
2
6
Bi MoO @PANI for the first six cycles at a scan rat of 0.1
2
6
−
1
mV s in the potential range of 0.01−3.00 V. All the CV
2
6
0
102, JCPDS, 2007), and the inset was the fast Fourier
curves exhibited multipeak features, revealing that the reaction
+
transform (FFT) images of the region, revealing the clear
steps between Li and the samples were multiple. It was
diffraction spots which could be ascribed to the high
obvious that the first curve was in parity with another five
48
crystallinity of the pristine Bi MoO . The TEM images of
curves which can be put down to the irreversible reactions and
2
6
49
Bi MoO @PANI composites were listed in Figure 4d,e, the
the formation of solid electrolyte interface (SEI) films.
2
6
rough PANI layers were obtained at the surfaces of Bi MoO
During the first negative scan, the peak at ∼1.53 V for pure
2
6
microspheres. Besides, the gray region of spheres were no
longer observed, testifying that the PANI were coated in the
both exterior and interior surfaces of Bi MoO spheres, which
Bi MoO (∼1.68 V for Bi MoO @PANI) might correspond to
2
6
2
6
+
the insertion of Li into layered structure of Bi MoO crystal,
2
6
while the small peak at ∼1.23 V (∼1.24 V) was associated with
2
6
50
may be ascribed to the hollow structure with open gaps and
the small size of aniline molecules. It could further be proved
in the HRTEM (Figure 4f), which reflected PANI was
the irreversible reaction of Bi MoO to Bi and Mo metal. An
2 6
evident peak at ∼0.34 V (∼0.40 V) can be ascribed to the
formation of SEI film, the alloying reaction between Bi and Li
21
deposited around Bi MoO6 crystals. The selected area
to form Li Bi and decomposition of MoO to Mo and Li O.
2
3
3
2
diffraction pattern (SEAD) of Bi MoO @PANI was exhibited
in Figure 4g, which clearly demonstrated the diffraction rings
and were related to the planes of (1 4 0), (2 0 0), (1 5 2), and
Nevertheless, the broad peak was separated into two small
peaks at ∼0.58 and ∼0.70 V (∼0.58 and ∼0.74 V) in
subsequent cycles, corresponding to the two electrochemical
2
6
51
(
3 2 0), respectively. Furthermore, the elemental mapping of
lithiation steps about Bi: the formation of LiBi and Li Bi. In
3
the selected microsphere (Figure 4h) attested the uniform
distributions of the C, N, Bi, Mo, and O elements, proving the
successful introduction of PANI again.
addition, other peaks in subsequent discharging processes were
responded to the different phase transition of bismuth
molybdate, lithium molybdates, Bi, and MoO . During the
3
According to above-mentioned analysis, the formation
mechanism of the Bi MoO @PANI was revealed in the
positive scan, the strongest peak at ∼1.0 V can be treated as
the dealloying process of Li Bi. Meanwhile, the two small
2
6
3
Scheme 1, which involves three steps (Supporting Information,
Experimental Section). First, the low crystallinity Bi MoO was
peaks at ∼1.40 and ∼2.44 V can be attributed to the oxidation
50−52
of Bi and Mo, respectively.
The above-mentioned major
2
6
acquired by the hydrothermal reaction of Bi2 and Mo , and
+
6+
reactions were listed in Table 2, and the Raman spectrum of
the XRD pattern of Bi MoO -precursor was exhibited in Figure
Bi MoO after first cycle was exhibited in Figure S4.
2
6
2
6
S3. Next, the as-obtained Bi MoO precursors were calcined in
Furthermore, all the reduction and oxidation peaks in the
CV curves exhibited an outstanding overlapped feature,
evidencing the good reversibility and stability of the electrode
during the electrochemical reactions.
2
6
nitrogen at 500 °C for 2 h, leading to the formation of high
crystallinity Bi MoO double spherical shells. Then, the aniline
2
6
monomers were dispersed in Bi MoO solutions and oxidative
2
6
polymerization reactions were occurred in the inner and outer
surfaces of Bi MoO sphere further calcined the products to
To further investigate the electrochemical reaction mecha-
nism, CV tests at different scan rates from 0.2 to 10 mV s−
were conducted and the curves were shown in Figure 5c,d and
S5. Both the cathodic peaks and anodic peaks were observed at
various scan rates and the current intensities were raised with
the increasing of scan rates. According to the previous
1
2
6
form the target composites of Bi MoO @PANI finally.
2
6
2
.2. Electrochemical Properties. The electrochemical
properties of the materials were evaluated by utilizing them as
an anode in a half-cell. The Li-ion storage mechanism of the
E
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure 5. CV curves at scan rate of 0.1 mv s− of (a) Bi MoO and (b) Bi MoO @PANI; CV curves at different scan rates of (c) Bi MoO and (d)
1
2
6
2
6
2
6
1
/2
Bi MoO @PANI. (e) Linear relation between I and v ; (f) lithium ions diffusion coefficients. Relation between log(i) and log(v) of peaks 1 and
2
6
p
2
for (g) Bi MoO and (h) Bi MoO @PANI. (i) The b values plotted against battery potential of Bi MoO @PANI for cathodic scans; the inset is
2
6
2
6
2
6
the current response plotted against scan rates of Bi MoO @PANI at various potentials. (j) Capacitive contribution (pink) and the diffusion
2
6
contribution (cyan) of Bi MoO @PANI; (k−l) ratio of capacitive contribution at various scan rates of Bi MoO @PANI and Bi MoO .
2
6
2
6
2
6
Table 2. Reaction Process
process
chemical equation
Bi MoO + xLi + xe− → Li Bi MoO
+
S1
S2
2
6
x
2
6
+
−
Li Bi MoO + (12 − x)Li + (12 − x)e → 2Bi + Mo + 6Li O
x
2
6
2
discharging
charging
+
−
+
Bi + Li e → LiBi
S3
−
LiBi + 2Li + 2e → Li Bi
3
Mo + 2Li O → MoO + 4Li
2
2
S4
S5
MoO + Li O → MoO + 2Li
2
2
3
2Bi + 3Li O → Bi O + 6Li + 6e−
+
+
2
2 3
5
3−55
reports,
the following equations were used to explore the
log(i) = b log(v) + log(a)
(3)
(4)
kinetic behavior of the electrode in detail.
1
/2
I = 2.69 × 10 n2/3AD
5
1/2 1/2
v
CLi
+
I(V) = k v + k v
1
2
p
(1)
(2)
In eq 1, n is the transform electrons in the reaction, A is the
contact area between the electrode and the electrolyte, D is the
b
i = av
F
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
−
1
Figure 6. Charge/discharge curves of (a) Bi MoO , (b) Bi MoO @PANI; (c) cycling performance at 100 mA g and (d) rate capability of two
2
6
2
6
samples. (e) Charge/discharge profiles of Bi MoO @PANI at different current densities.
2
6
+
diffusion coefficient, CLi is the concentration of lithium ions,
and v and Ip are the scan rate and the peak current,
nated by the pseudocapacitive behaviors. Furthermore, b values
plotted against potential for cathodic scans of Bi MoO and
2
6
+
respectively. D can be calculated by the linear fitting of
Bi MoO @PANI were exhibited in Figures S6a and 5i. The
Li
2 6
1
/2
I −v , after calculating, the values of slope of oxidation/
stronger capacitive-controlled behavior of Bi MoO @PANI
2 6
p
reduction peaks were 1.55/−1.70 and 2.06/−2.27 for
was shown, which disclosed the fundamental origin of the
rapid charge/discharge rate and remarkable cyclic durability.
The inset was the current response plotted against scan rates at
various potentials. In addition, through the Trasatti analysis,
the capacitive contributions at different scan rates were
Bi MoO and Bi MoO @PANI (Figure 5e), respectively, and
2
6
2
6
−
13
the associated diffusion coefficients were 9.17 × 10 /5.19 ×
−
13
−11
−11
1
0
and 3.01 × 10 /1.69 × 10 , respectively. It was
obvious in Figure 5f that the diffusion coefficients of
Bi MoO @PANI were larger than that of Bi MoO , corre-
sponding to higher Li-ion shuttle rate owing to the superior
conductive of PANI layer.
The capacity of batteries mainly came from two parts: (a) a
diffusion-controlled intercalation/conversion/alloying process
and (b) the capacitive process that involved faradaic
pseudocapacitive behaviors and non-Faradaic electric double
layer process. According to the eqs 2 and 3, the slope of
log(v)−log(i) plots of redox peaks can be used to explain the
Li-ion insertion mechanism, while a b-value approaching 1
implies the capacitive-controlled behaviors and approaching to
.5 corresponds to the diffusion-controlled behaviors. As
shown in Figure 5g, the b-values of peaks 1 and 2 of pure
Bi MoO were 0.54 and 0.67, respectively, both close to 0.5,
indicating the diffusion-controlled behaviors prevailed. Mean-
while, the b-values of peaks 1 and 2 of Bi MoO @PANI were
1/2
2
6
2
6
quantitatively calculated. On the basis of eq 4, k v and k v
1
2
are relation with the contributions of surface pseudocapacitive
behaviors and the diffusion-controlled process, respectively.
1
/2
1/2
Typically, the fitted lines of I/v −v and the detail-fitting
−
1
curve for pseudocapacitive contribution at 0.2 mV s of
Bi MoO @PANI were displayed in Figures S6b and 5j,
2
6
respectively. The fraction of capacitive contribution (71.4%)
was found (red region), while the capacitive contribution
(
s
Figure 5k) at different scan rates of 0.1, 0.5, 0.8, and 1.0 mV
−
1
were 62.0, 77.4, 83.3, and 87.6%, respectively, indicating
that the pseudocapacitive contribution of capacity was
increased at high current density. Besides, the pseudocapacitive
0
contributions of pure Bi MoO (Figure 5l) were 34.3, 46.1,
2
6
2
6
56.2, 66.1, and 72.4% at various scan rates, respectively, which
were lower than that of Bi MoO @PANI, deducing that the
2
6
2
6
0
.81 and 0.89 (Figure 5h), respectively, demonstrating that the
enhanced capacitive behaviors mainly derived from the
introduction of PANI. The enlarged capacitive contribution
electrochemical properties for Bi MoO @PANI were domi-
2
6
G
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure 7. SEM images of (a, b) Bi MoO and (c, d) Bi MoO @PANI after 200 cycles; (e) the buffer effect of PANI layer.
2
6
2
6
Table 3. Comparison of Present Work with Reported Binary and Ternary Metal oxides Materials
original cyclability capacity (mAh g−1)
(cycles)
retention
(%)
composite cyclability capacity (mAh g−1)
(cycles)
retention
(%)
materials/composite
Fe O /Fe O @CNTs
ref
−
1
−1
246 (50) at 50 mA g
447 (20) at 74 mA g
27
58
70
46
33
9
39
39
84
31
33
32
68
38
30
36
619 (80) at 50 mA g
750 (20) at 74 mA g
89
94
65
76
62
81
60
84
82
80
75
53
61
75
37
82
56
57
58
59
6
60
61
62
26
21
63
64
65
66
29
2
3
2
3
−
1
−1
Co O /Co O @carbon spheres
3
4
3
4
−
1
−1
TiO /TiO @PANI
121.2 (50) at 1500 mA g
92 (25) at 30.7 mA g−
300 (100) at 100 mA g−
58 (1200) at 200 mA g−
292.5 (50) at 300 mA g−
151.7 (50) at 1500 mA g
2
2
1
171 (25) at 30.7 mA g−1
480 (100) at 100 mA g−1
MoO /MoO @PANI
3
3
1
SnO /SnO @PANI
2
2
1
−1
WO /WO @PANI
516 (1200) at 200 mA g
607.3 (50) at 300 mA g
3
3
1
−1
ZnFe O /ZnFe O @PANI
2
4
2
4
1
−1
GeO /GeO @PANI@rGO
144.6 (100) at 200 mA g−
300 (15) at 0.1 mA cm−
123 (100) at 100 mA g−
321 (85) at 100 mA g−
321 (100) at 100 mA g−
280.4 (100) at 100 mA g−
330.4 (100) at 100 mA g−
366.1 (50) at 600 mA g−
288.7 (200) at 100 mA g−
748.8 (100) at 200 mA g
2
2
2
−2
MoO /MoO @PANI
530 (15) at 0.1 mA cm
719 (100) at 100 mA g
735 (200) at 100 mA g
628 (100) at 100 mA g
2
2
1
−1
Bi MoO /Bi MoO @rGO
2
6
2
6
1
−1
CoMoO /CoMoO @Graphene
4
4
1
−1
CoMoO /CoMoO @rGO
4
4
1
1
−1
ZnMoO /ZnMoO @rGO
632 (100) at 100 mA g
4
4
−1
NiCo O /NiCo O @GO
789.9 (100) at 100 mA g
2
4
2
4
1
491 (50) at 600 mA g−1
Zn SnO /Zn SnO @PANI
2
4
2
4
1
656.3 (200) at 100 mA g−1
Bi MoO /Bi MoO @PANI
this work
2
6
2
6
1
could bring remarkable cyclic stability and fast charge/
discharge rate.
displayed a low capacity of 288.7 mAh g− at 200 cycles with a
capacity retention of 36%. Obviously, the introduction of
PANI can effectively improve the cyclic durability on account
of the protection of PANI conductive layer for the structural
change during the charge/discharge processes. Additionally, as
shown in Figure S7, only a poor capacity of 213.2 mAh g− was
delivered by the Bi MoO nanoparticles at 200 cycles along
The galvanostatic charge/discharge cycle performances of
−
1
the samples were tested at a current density of 100 mA g
+
over the range of 0.01−3 V (vs Li /Li). The charge/discharge
voltage profiles of Bi MoO and Bi MoO @PANI at various
1
2
6
2
6
cycles were showed in Figure 6a,b, and the sloped plateaus
were matched well with the relative peaks in the CV curves.
The initial discharge capacities of Bi MoO and Bi MoO @
2
6
with a capacity retention of 23%, proving the hollow structure
can buffer volume change and exhibit better cyclic stability.
In addition, the rate properties were further carried out at
stepwise current densities of 0.1, 0.2, 0.4, 0.8, and 1.6 A g . As
shown in Figure 6d, the better capacities of Bi MoO @PANI
were acquired, delivered 701.3, 655.3, 586.9, 484.2, and 355.5
mAh g , respectively. It was visualized that the specific
capacities of pure Bi MoO were unsatisfactory and only
exhibited 207.6 mAh g at a current density of 1.6 A g .
2
6
2
6
−
1
PANI were 958.9 and 1011.7 mAh g , which were higher than
−
1
−1
the initial charge capacities of 754.8 and 763.5 mAh g ,
delivering Coulombic efficiency (CE) of 78.72 and 75.46%,
respectively. The capacity loss at the first cycle can be ascribed
to the irreversible redox reaction and the formation of SEI
films, which was usual for most transition metal oxide anodes,
and the redox processes became steady after the first cycle,
bringing about the stable Coulombic efficiencies. Expectably,
the capacity retention of Bi MoO @PANI was much higher
2
6
−
1
2
6
−
1
−1
−
1
Furthermore, when the current density came back to 0.1 A g
−
1
after a high current of 1.6 A g , the capacity of Bi MoO @
2
6
2
6
1
than that of pure Bi MoO , which could be clearly evidenced
PANI could cheeringly recover to 674.5 mAh g− and be
maintained for 22 cycles. Sure enough, the rate performance of
Bi MoO @PANI composites was better than that of pure
2
6
in Figure 6c. As we can see that the Bi MoO @PANI
2
6
−
1
composite delivered a capacity of 656.3 mAh g after 200
cycles with a huge capacity retention of 82% compared with
the capacity at second cycle, while the capacity of pure
Bi MoO exhibited continuous fading during cycling and only
2
6
Bi MoO , which could be attributed to the faster electrons
transfer on account of the conductive layer of PANI thus the
redox reactions can take place fleetly. Moreover, the protective
2
6
2
6
H
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
1
/2
Figure 8. (a) Pristine EIS curves; Nyquist plots at various cycles of (b) Bi MoO , (c) Bi MoO @PANI. (d) Linear relation between ω and Z″ at
2
6
2
6
various cycles of Bi MoO @PANI; (e) diffusion coefficients at different cycles. (f) Various phase evolutions and (g) the Nyquist plots at different
2
6
potentials of Bi MoO @PANI.
2
6
6
7
layer of PANI can effectively hinder the structural
fragmentation of electrode materials further displayed excellent
cyclic stability. Besides, the outstanding rate performance of
Bi MoO @PANI was evidenced by the stable platforms at
films, and the resistance of charge transfer, respectively. The
values of the corresponding parameters after fitting were listed
in Table S1. The similar R between the two samples was
ascribed to the same electrolyte and fabrication parameters.
e
2
6
stepwise current densities in Figure 6e, reflecting the lower
pulverization. Furthermore, SEM tests of the electrode
materials after 200 charge/discharge cycles were carried out
to prove the protective effect of PANI coating. As resulted in
Figure 7, a circular structure was maintained on account of the
buffering effect of hollow cavity. Notably, it was clear that the
PANI protective layer still existed on the surfaces of Bi MoO
The interface impedance (Rint = R
480.15 Ω, while that of Bi MoO
Obviously, Bi MoO @PANI reflected smaller charge-transfer
resistance compared to bare Bi MoO , illuminating that the
f
+ Rct) of Bi
2 6
MoO was
@PANI was 356.5 Ω.
2
6
2
6
2
6
introduction of PANI not only can boost the conductivity of
the materials, but promote rapid charge transfer and enhanced
reaction kinetics. In addition, the Nyquist plots of the two
samples at 20, 50, 80, 100, 120, 150, and 200t loops at around
.8 V (vharging) were exhibited in Figure 8b,c, respectively. As
we can see that the impedances of Bi MoO were higher than
Bi MoO @PANI in the associated loops, testifying to the
above-mentioned positive effects coming from the introduction
of PANI again. Furthermore, in terms of the above equivalent
2
6
sphere after 200 cycles, protecting the structural integrality and
preventing the active material from directly exposing to the
electrolyte. In conclusion, the PANI protective layer effectively
protected the structure thus remarkably improved the cyclic
stability. In light of previous reports, many studies focus on
solving the problem of severe capacity fading upon repeated
discharge/charge cycling by hybridizing those metal oxides and
ternary metal oxides with carbon-based materials (see details in
Table 3).
0
2
6
2
6
68,69
circuit model and the following equations,
the diffusion
coefficient from the low frequency regions could be computed.
ω = 2πf
(5)
(6)
The enhanced cyclic durability and rate performance of
Bi MoO @PANI may be closely connected with their superior
−1/2
2
6
Z = R + R + R + σω
re
e
f
ct
conductivity coming from the introduction of PANI, which
could be demonstrated by electrochemical impedance spec-
troscopy (EIS) analysis. The Nyquist plots of fresh cells were
showed in Figure 8a, the line in low frequency corresponds to
the solid-state diffusion impedance and the semicircle in high
frequency is in relation to charge-transfer impedance. The
relative equivalent circuit model was displayed in the inset, in
which R , R , and R stand for the resistance of materials
2
2
2 4 4 2 2
D = R T /2S n F C σ
According to eq 5 and 6, the lines fitting of Z″−ω
(7)
of
−
1/2
Bi MoO and Bi MoO @PANI were displayed in Figures S8
and 8d, and the corresponding slopes of σ were acquired. In eq
2
6
2
6
−
1
−1
7, R is the gas constant (8.314 J mol K ), T is Kevin
2
temperature (293.15K), S is the electrode area (1.54 cm ), n is
e
f
ct
(
electrode, electrolyte, and separation), the resistance of SEI
the electronic transfer number, F is the Faraday constant, C is
I
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
the concentration of lithium ions, and σ is the Warburg factor
Detailed experimental section, related characterization
results, and electrochemical data (PDF)
resulting from eq 6. The lithium ion diffusion coefficients
+
Li
(
D ) of Bi MoO and Bi MoO @PANI were reflected in
2
6
2
6
Table S2. As clearly indicated in Figure 8e, the lithium ion
AUTHOR INFORMATION
diffusion coefficients of Bi MoO @PANI were higher than that
■
2
6
of Bi MoO at each cycle, testifying the PANI can realize
Corresponding Author
*E-mail: gq-zou@csu.edu.cn.
ORCID
Hongshuai Hou: 0000-0001-8201-4614
Xiaobo Ji: 0000-0002-5405-7913
Notes
2
6
enhanced conductivity and rapid charge transfer further afford
an improvement of the electrochemical performances.
The CV curves of Bi MoO and Bi MoO @PANI after 200
2
6
2
6
−
1
cycles at scan rate of 0.2 mV s were listed in Figure S9. The
related reduction and oxidation peaks all existed, and the peak
currents of Bi MoO @PANI were higher than that of pure
2
6
Bi MoO , indicating the stronger reaction. Moreover, the in
The authors declare no competing financial interest.
2
6
situ EIS of Bi MoO and Bi MoO @PANI at various voltages
2
6
2
6
during the 200 cycles were further explored. The charge/
discharge curve of Bi MoO @PANI at 200 cycle was shown in
ACKNOWLEDGMENTS
■
2
6
This work was financially supported by National Key Research
and Development Program of China (2018YFC1901605), the
National Postdoctoral Program for Innovative Talents
Figure 8f, and a series of voltage points were selected as well as
the different EIS curves were displayed in Figure 8g.
Obviously, during the discharge process, Rtotal in the high
frequency range was decreasing, derived from the formation of
(
BX201600192), Hunan Provincial Science and Technology
Plan (2017TP1001, 2016TP1009),National Natural Science
Foundation of China (51622406, 21673298, 21473258),Young
Elite Scientists Sponsorship Program By CAST
2017QNRC001), Fundamental Research Funds for the
Central Universities of Central South University
2018zzts368), Project of Innovation Driven Plan in Central
+
fluffy structure after the insertion of Li which offered
distensible ion diffusion channel thus realized rapid electron/
ion transfer, and the worse conductivity of relative metal
oxides. Besides, comparing the Nyquist plots and the lines
(
−
1/2
fitting of Z″−ω of Bi MoO (Figure S10) and Bi MoO @
2
6
2
6
(
+
Li
PANI (Figure S11), the D of the two samples could be
South (2017CX004, 2018CX005).
evaluated and are shown in Figure S12. It was clear that the
+
Li
Bi MoO @PANI exhibited smaller resistances and higher D
2
6
REFERENCES
■
than that of pristine Bi MoO , proving the higher electro-
2
6
(
1) Ko, M.; Chae, S.; Ma, J.; Kim, N.; Lee, H. W.; Cui, Y.; Cho, J.
Scalable synthesis of silicon-nanolayer-embedded graphite for high-
energy lithium-ion batteries. Nat. Energy. 2016, 1, 16113.
2) Reddy, M. V.; Subba Rao, G. V.; Chowdari, B. V. Metal oxides
chemical conductivity.
. CONCLUSION
In this work, the Bi MoO with double-layered spherical shells
3
(
2
6
and oxysalts as anode materials for Li ion batteries. Chem. Rev. 2013,
structure was successfully prepared by the self-assembly of Bi−
Mo processor. Owing to the open hollow-structure sphere and
the small size of aniline molecules, the PANI conductive layers
were coated on the inner and outer surfaces of pristine
Bi MoO thus obtained the Bi MoO @PANI composites.
113, 5364−5457.
(3) Zhang, F.; Qi, L. Recent Progress in Self-Supported Metal Oxide
Nanoarray Electrodes for Advanced Lithium-Ion Batteries. Adv. Sci.
2
(
016, 3, 1600049.
4) Meduri, P.; Clark, E.; Kim, J. H.; Dayalan, E.; Sumanasekera, G.
2
6
2
6
U.; Sunkara, M. K. MoO3‑x Nanowire Arrays As Stable and High-
Capacity Anodes for Lithium Ion Batteries. Nano Lett. 2012, 12,
Benefiting from the double-PANI layers, Bi MoO @PANI
2
6
exhibited enhanced electrical conductivity and excellent cyclic
stability. Remarkably, when utilized as anode in LIBs, the
1
(
784−1788.
5) He, C.; Wu, S.; Zhao, N.; Shi, C.; Liu, E.; Li, J. Carbon-
encapsulated Fe O nanoparticles as a high-rate lithium ion battery
Bi MoO @PANI composite delivered a high capacity of 656.3
2
6
3
4
−
1
−1
mAh g after 200 cycles at 100 mA g with a capacity
retention rate of 82%, while the pure Bi MoO only delivered
88.7 mAh g with a low capacity retention rate of 36%.
anode material. ACS Nano 2013, 7, 4459−4469.
(6) Ding, H.; Jiang, H.; Zhu, Z.; Hu, Y.; Gu, F.; Li, C. Ternary
2
6
−
1
2
SnO
lithium-ion batteries. Electrochim. Acta 2015, 157, 205−210.
7) Wang, X.; Guan, H.; Chen, S.; Li, H.; Zhai, T.; Tang, D.; Bando,
Y.; Golberg, D. Self-stacked Co O nanosheets for high-performance
@PANI/rGO nanohybrids as excellent anode materials for
2
Additionally, with the assistance of the particular kinetic
analysis, the prominent pseudocapacitive behaviors and low
electron/ion transferring resistance of Bi MoO @PANI
(
3
4
2
6
lithium ion batteries. Chem. Commun. 2011, 47, 12280−12282.
composites were shown, revealing that the introduction of
PANI was significant for ultrastable energy storage and rapid
electron/ion transport. After cycling, the in situ EIS analysis at
various cycles and different voltages confirmed the enhanced
electrical conductivities of the electrode. This work reports a
simple manner to acquire PANI conductive layers, confirming
that the combination with PANI is an effective way to achieve
ultrastable electrochemical performances, and sheds light on
the detailed analysis methods of interfacial properties.
(8) Cabana, J.; Monconduit, L.; Larcher, D.; Palacin, M. R. Beyond
intercalation-based Li-ion batteries: the state of the art and challenges
of electrode materials reacting through conversion reactions. Adv.
Mater. 2010, 22, E170−E192.
(9) Lin, Y.; Li, T.; Zhao, F.; Han, L.; Wang, Z.; Wu, Y.; He, Q.;
Wang, J.; Huo, L.; Sun, Y.; et al. Structure Evolution of Oligomer
Fused-Ring Electron Acceptors toward High Efficiency of As-Cast
Polymer Solar Cells. Adv. Energy Mater. 2016, 6, 1600854.
(10) Shen, L.; Yu, L.; Yu, X. Y.; Zhang, X.; Lou, X. W. Self-
Templated Formation of Uniform NiCo O Hollow Spheres with
2
4
Complex Interior Structures for Lithium-Ion Batteries and Super-
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.inorg-
chem.9b00627.
■
capacitors. Angew. Chem. 2015, 127, 1888−1892.
*
S
(11) Wang, S.; Yang, X.; Zhang, X.; Ding, X.; Yang, Z.; Dai, K.;
Chen, H. A plate-on-plate sandwiched Z-scheme heterojunction
photocatalyst: BiOBr-Bi MoO with enhanced photocatalytic per-
2
6
formance. Appl. Surf. Sci. 2017, 391, 194−201.
J
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
(
12) Li, J.; Liu, X.; Sun, Z.; Pan, L. Mesoporous yolk-shell structure
(29) Zhao, Y.; Huang, Y.; Xue, L.; Sun, X.; Wang, Q.; Zhang, W.;
Wang, K.; Zong, M. Polyaniline(PANI) coated Zn SnO cube as
Bi MoO6 microspheres with enhanced visible light photocatalytic
2
2
4
activity. Ceram. Int. 2015, 41, 8592−8598.
anode materials for lithium batteries. Polym. Test. 2013, 32, 1582−
(
13) Yang, Z.; Shen, M.; Dai, K.; Zhang, X.; Chen, H. Controllable
1587.
synthesis of Bi MoO nanosheets and their facet-dependent visible-
(30) Yang, L.; Wang, S.; Mao, J.; Deng, J.; Gao, Q.; Tang, Y.;
2
6
light-driven photocatalytic activity. Appl. Surf. Sci. 2018, 430, 505−
14.
14) Zhao, W.; Li, C.; Wang, A.; Lv, C.; Zhu, W.; Dou, S.; Wang, Q.;
Schmidt, O. G. Hierarchical MoS /polyaniline nanowires with
excellent electrochemical performance for lithium-ion batteries. Adv.
Mater. 2013, 25, 1180−1184.
(31) Chen, C.; Wen, Y.; Hu, X.; Ji, X.; Yan, M.; Mai, L.; Hu, P.;
Shan, B.; Huang, Y. Na(+) intercalation pseudocapacitance in
graphene-coupled titanium oxide enabling ultra-fast sodium storage
and long-term cycling. Nat. Commun. 2015, 6, 6929.
2
5
(
Zhong, Q. Polyaniline decorated Bi2MoO6 nanosheets with effective
interfacial charge transfer as photocatalysts and optical limiters. Phys.
Chem. Chem. Phys. 2017, 19, 28696−28709.
(
15) Tang, D.; Mabayoje, O.; Lai, Y.; Liu, Y.; Mullins, C. B.
Enhanced Photoelectrochemical Performance of Porous Bi MoO
2
6
(32) Branzoi, V.; Pilan, L.; Branzoi, F. Nanocomposite Films
̂ ̂
Obtained by Electrochemical Codeposition of Conducting Polymers
Photoanode by an Electrochemical Treatment. J. Electrochem. Soc.
017, 164, H299−H306.
16) Zhao, W.; Wang, A.; Wang, Y.; Lv, C.; Zhu, W.; Dou, S.; Wang,
Q.; Zhong, Q. Accessible fabrication and mechanism insight of
heterostructured BiOCl/Bi MoO /g-C N nanocomposites with
2
(
and Carbon Nanotubes. Electroanalysis 2009, 21, 557−562.
(33) Kawakita, J.; Miura, T.; Kishi, T. Lithium insertion and
extraction kinetics of Li1+xV3O . J. Power Sources 1999, 83, 79−83.
8
2
6
3
4
(34) Ge, P.; Hou, H.; Banks, C. E.; Foster, C. W.; Li, S.; Zhang, Y.;
efficient photosensitized activity. J. Alloys Compd. 2017, 726, 164−
72.
17) Zhao, W.; Li, C.; Wang, A.; Lv, C.; Zhu, W.; Dou, S.; Wang, Q.;
He, J.; Zhang, C.; Ji, X. Binding MoSe with carbon constrained in
2
1
(
carbonous nanosphere towards high-capacity and ultrafast Li/Na-ion
storage. Energy Storage Materials 2018, 12, 310−323.
Zhong, Q. Polyaniline decorated Bi2MoO6 nanosheets with effective
interfacial charge transfer as photocatalysts and optical limiters. Phys.
Chem. Chem. Phys. 2017, 19, 28696−28709.
(35) Deng, Z.; Jiang, H.; Hu, Y.; Liu, Y.; Zhang, L.; Liu, H.; Li, C.
3
D Ordered Macroporous MoS @C Nanostructure for Flexible Li-
2
Ion Batteries. Adv. Mater. 2017, 29, 1603020.
36) Wu, F.; Wang, X.; zheng, W.; Gao, H.; Hao, C.; Ge, C.
Synthesis and characterization of hierarchical Bi MoO /Polyaniline
(
18) Chen, W.-b.; Zhang, L.-n.; Ji, Z.-j.; Zheng, Y.-d.; Yuan, S.;
(
Wang, Q. Self-Supported Bi MoO Nanosheet Arrays as Advanced
2
6
2
6
Integrated Electrodes for Li-Ion Batteries with Super High Capacity
and Long Cycle Life. Nano 2018, 13, 1850066.
nanocomposite for all-solid-state asymmetric supercapacitor. Electro-
chim. Acta 2017, 245, 685−695.
(
19) Zheng, Y.; Zhou, T.; Zhao, X.; Pang, W. K.; Gao, H.; Li, S.;
(37) Wang, H.; Song, Y.; Zhou, J.; Xu, X.; Hong, W.; Yan, J.; Xue,
Zhou, Z.; Liu, H.; Guo, Z. Atomic Interface Engineering and Electric-
R.; Zhao, H.; Liu, Y.; Gao, J. High-performance supercapacitor
materials based on polypyrrole composites embedded with core-
Field Effect in Ultrathin Bi MoO Nanosheets for Superior Lithium
2
6
Ion Storage. Adv. Mater. 2017, 29, 1700396.
20) Yuan, S.; Zhao, Y.; Chen, W.; Wu, C.; Wang, X.; Zhang, L.;
Wang, Q. Self-Assembled 3D Hierarchical Porous Bi MoO Micro-
sheath polypyrrole@MnMoO nanorods. Electrochim. Acta 2016, 212,
4
(
7
(
75−783.
2
6
38) Liu, H.; Zhang, F.; Li, W.; Zhang, X.; Lee, C. S.; Wang, W.;
spheres toward High Capacity and Ultra-Long-Life Anode Material
Tang, Y. Porous tremella-like MoS /polyaniline hybrid composite
2
for Li-Ion Batteries. ACS Appl. Mater. Interfaces 2017, 9, 21781−
with enhanced performance for lithium-ion battery anodes. Electro-
chim. Acta 2015, 167, 132−138.
2
(
1790.
21) Zhai, X.; Gao, J.; Xue, R.; Xu, X.; Wang, L.; Tian, Q.; Liu, Y.
(39) Bi, J.; Fang, W.; Li, L.; Li, X.; Liu, M.; Liang, S.; Zhang, Z.; He,
Facile synthesis of Bi MoO /reduced graphene oxide composites as
2
6
Y.; Lin, H.; Wu, L.; et al. Ternary reduced-graphene-oxide/Bi MoO /
2
6
anode materials towards enhanced lithium storage performance. J.
Colloid Interface Sci. 2018, 518, 242−251.
Au nanocomposites withenhanced photocatalytic activity under
visible light. J. Alloys Compd. 2015, 649, 28−34.
(
22) Weng, W.; Lin, J.; Du, Y.; Ge, X.; Zhou, X.; Bao, J. Template-
(40) Wang, P.; Ao, Y.; Wang, C.; Hou, J.; Qian, J. A one-pot method
free synthesis of metal oxide hollow micro-/nanospheres via Ostwald
for the preparation of graphene−Bi2MoO6 hybrid photocatalysts that
are responsive to visible-light and have excellent photocatalytic
activity in the degradation of organic pollutants. Carbon 2012, 50,
ripening for lithium-ion batteries. J. Mater. Chem. A 2018, 6, 10168−
1
(
0175.
23) Park, J. S.; Jeong, S. Y.; Jeon, K. M.; Kang, Y. C.; Cho, J. S. Iron
5
(
256−5264.
diselenide combined with hollow graphitic carbon nanospheres as a
high-performance anode material for sodium-ion batteries. Chem. Eng.
J. 2018, 339, 97−107.
41) Hardcastle, F. D.; Wachs, I. E. Molecular structure of
molybdenum oxide in bismuth molybdates by Raman spectroscopy.
J. Phys. Chem. 1991, 95, 10763−10772.
(
24) Hu, S.; Chen, W.; Zhou, J.; Yin, F.; Uchaker, E.; Zhang, Q.;
(
42) Zhang, L.; Wan, M. Polyaniline/TiO Composite Nanotubes. J.
Cao, G. Preparation of carbon coated MoS flower-like nanostructure
2
2
Phys. Chem. B 2003, 107, 6748−6753.
43) Zhao, Y.; Manthiram, A. High-Capacity, High-Rate Bi-Sb Alloy
Anodes for Lithium-Ion and Sodium-Ion Batteries. Chem. Mater.
015, 27, 3096−3101.
44) Jasieniak, J. J.; Treat, N. D.; McNeill, C. R.; de Villers, B. J.;
Della Gaspera, E.; Chabinyc, M. L. Interfacial Characteristics of
with self-assembled nanosheets as high-performance lithium-ion
(
battery anodes. J. Mater. Chem. A 2014, 2, 7862−7872.
(
25) Zhang, J.; Chu, R.; Chen, Y.; Jiang, H.; Zhang, Y.; Huang, N.
2
(
M.; Guo, H. Electrodeposited binder-free NiCo O @carbon nano-
2
4
fiber as a high performance anode for lithium ion batteries.
Nanotechnology 2018, 29, 125401.
Efficient Bulk Heterojunction Solar Cells Fabricated on MoO Anode
(
26) Qi, Y.; Yang, X.; Chen, W. MoO2 and PANI/MoO2
x
Nanocomposites as Anode Materials for Lithium-ion Batteries. Adv.
Interlayers. Adv. Mater. 2016, 28, 3944−3951.
OptoElectron. Energy Environ. 2013, ASa3A.30.
(45) Kulkarni, S.; Patil, U.; Shackery, I.; Sohn, J.; Lee, S.; Park, B.;
Jun, S. High-performance supercapacitor electrode based on a
polyaniline nanofibers/3D graphene framework as an efficient charge
transporter. J. Mater. Chem. A 2014, 2, 4989−4998.
(46) Sreedhar, B.; Sairam, M.; Chattopadhyay, D. K.; Mitra, P. P.;
Rao, D. V. M. Thermal and XPS studies on polyaniline salts prepared
by inverted emulsion polymerization. J. Appl. Polym. Sci. 2006, 101,
499−508.
(47) Luo, Y.; Kong, D.; Jia, Y.; Luo, J.; Lu, Y.; Zhang, D.; Qiu, K.; Li,
C.; Yu, T. Self-assembled graphene@PANI nanoworm composites
(
27) Jeong, J. M.; Choi, B. G.; Lee, S. C.; Lee, K. G.; Chang, S. J.;
Han, Y. K.; Lee, Y. B.; Lee, H. U.; Kwon, S.; Lee, G.; et al.
Hierarchical hollow spheres of Fe O @polyaniline for lithium ion
2
3
battery anodes. Adv. Mater. 2013, 25, 6250−6255.
(
28) Zhang, F.; Yang, C.; Gao, X.; Chen, S.; Hu, Y.; Guan, H.; Ma,
Y.; Zhang, J.; Zhou, H.; Qi, L. SnO @PANI Core-Shell Nanorod
2
Arrays on 3D Graphite Foam: A High-Performance Integrated
Electrode for Lithium-Ion Batteries. ACS Appl. Mater. Interfaces 2017,
9, 9620−9629.
K
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
with enhanced supercapacitor performance. RSC Adv. 2013, 3, 5851−
performance anodes for lithium-ion batteries. J. Alloys Compd. 2018,
731, 1095−1102.
5
859.
(
48) Yang, X.; Yang, Y.; Hou, H.; Zhang, Y.; Fang, L.; Chen, J.; Ji, X.
(67) Zhou, Q.; Liu, L.; Huang, Z.; Yi, L.; Wang, X.; Cao, G. Co S @
3 4
Size-Tunable Single-Crystalline Anatase TiO2 Cubes as Anode
Materials for Lithium Ion Batteries. J. Phys. Chem. C 2015, 119,
polyaniline nanotubes as high-performance anode materials for
sodium ion batteries. J. Mater. Chem. A 2016, 4, 5505−5516.
(68) Song, W. X.; Hou, H. S.; Ji, X. B. Progress in the Investigation
3
(
923−3930.
49) Jing, M.; Li, F.; Chen, M.; Long, F.; Wu, T. Binding ZnO
and Application of Na
Acta Phys-Chim. Sin. 2017, 1, 103−129.
69) Song, W.; Ji, X.; Wu, Z.; Zhu, Y.; Yao, Y.; Huangfu, K.; Chen,
Q.; Banks, C. Na FePO cathode utilized in hybrid-ion batteries: a
3 2 4 3
V (PO ) for Electrochemical Energy Storage.
nanorods in reduced graphene oxide via facile electrochemical method
(
for Na-ion battery. Appl. Surf. Sci. 2019, 463, 986−993.
(
50) Ette, P. M.; Gurunathan, P.; Ramesha, K. Self-assembled
2
4
mechanistic exploration of ion migration and diffusion capability. J.
Mater. Chem. A 2014, 2, 2571−2577.
lamellar alpha -molybdenum trioxide as high performing anode
material for lithium-ion batteries. J. Power Sources 2015, 278, 630−
6
38.
(
51) Li, Y.; Trujillo, M. A.; Fu, E.; Patterson, B.; Fei, L.; Xu, Y.;
Deng, S.; Smirnov, S.; Luo, H. Bismuth Oxide: A New Lithium-Ion
Battery Anode. J. Mater. Chem. A 2013, 1, 12123−12127.
(
52) Wang, Z.; Madhavi, S.; Lou, X. W. Ultralong α-MoO3
Nanobelts: Synthesis and Effect of Binder Choice on Their Lithium
Storage Properties. J. Phys. Chem. C 2012, 116, 12508−12513.
(
53) Augustyn, V.; Come, J.; Lowe, M. A.; Kim, J. W.; Taberna, P.
L.; Tolbert, S. H.; Abruna, H. D.; Simon, P.; Dunn, B. High-rate
̃
+
electrochemical energy storage through Li intercalation pseudocapa-
citance. Nat. Mater. 2013, 12, 518−522.
(
54) Wang, J.; Polleux, J.; Lim, J.; Dunn, B. Pseudocapacitive
Contributions to Electrochemical Energy Storage in TiO (Anatase)
2
Nanoparticles. J. Phys. Chem. C 2007, 111, 14925−14931.
(
55) Ge, P.; Li, S.; Xu, L. Q.; Zou, K. Y.; Gao, X.; Cao, X. Y.; Zou, G.
Q.; Hou, H. S.; Ji, X. B. Hierarchical Hollow-Microsphere Metal-
Selenide@Carbon Composites with Rational Surface Engineering for
Advanced Sodium Storage. Adv. Energy Mater. 2019, 9, 1803035.
(
56) Sun, Y.; Zhang, J.; Huang, T.; Liu, Z.; Yu, A. Fe O /CNTs
2 3
composites as anode materials for lithium-ion batteries. Int. J.
Electrochem. Sci. 2013, 8, 2918−2931.
(
57) Zhan, L.; Wang, Y.; Qiao, W.; Ling, L.; Yang, S. Hollow carbon
spheres with encapsulation of Co O nanoparticles as anode material
3
4
for lithium ion batteries. Electrochim. Acta 2012, 78, 440−445.
(
58) Lai, C.; Zhang, H. Z.; Li, G. R.; Gao, X. P. Mesoporous
polyaniline/TiO2 microspheres with core-shell structure as anode
materials for lithium ion battery. J. Power Sources 2011, 196, 4735−
4
(
740.
59) Mohan, V. M.; Chen, W.; Murakami, K. Synthesis, structure
and electrochemical properties of polyaniline/MoO3 nanobelt
composite for lithium battery. Mater. Res. Bull. 2013, 48, 603−608.
(
60) Zhang, K.; Li, N.; Wang, Y.; Ma, X.; Zhao, J.; Qiang, L.; Hou,
S.; Ji, J.; Li, Y. Bifunctional urchin-like WO @PANI electrodes for
3
superior electrochromic behavior and lithium-ion battery. J. Mater.
Sci.: Mater. Electron. 2018, 29, 14803−14812.
(
61) Wang, K.; Huang, Y.; Wang, D.; Zhao, Y.; Wang, M.; Chen, X.;
Qin, X.; Li, S. Preparation and application of hollow ZnFe O @PANI
2
4
hybrids as high performance anode materials for lithium-ion batteries.
RSC Adv. 2015, 5, 107247−107253.
(
62) Sarkar, S.; Borah, R.; Santhosha, A. L.; Dhanya, R.; Narayana,
C.; Bhattacharyya, A. J.; Peter, S. C. Heterostructure composites of
rGO/GeO /PANI with enhanced performance for Li ion battery
2
anode material. J. Power Sources 2016, 306, 791−800.
(
63) Xu, J.; Gu, S.; Fan, L.; Xu, P.; Lu, B. Electrospun Lotus Root-
like CoMoO @Graphene Nanofibers as High-Performance Anode for
4
Lithium Ion Batteries. Electrochim. Acta 2016, 196, 125−130.
(
64) Yang, T.; Zhang, H.; luo, Y.; Mei, L.; Guo, D.; Li, Q.; Wang, T.
Enhanced electrochemical performance of CoMoO4 nanorods/
reduced graphene oxide as anode material for lithium-ion batteries.
Electrochim. Acta 2015, 158, 327−332.
(
65) Xue, R.; Hong, W.; Pan, Z.; Jin, W.; Zhao, H.; Song, Y.; Zhou,
J.; Liu, Y. Enhanced electrochemical performance of ZnMoO4/
reduced graphene oxide composites as anode materials for lithium-ion
batteries. Electrochim. Acta 2016, 222, 838−844.
(
66) Rong, H.; Qin, Y.; Jiang, Z.; Jiang, Z.-J.; Liu, M. A novel
NiCo O @GO hybrid composite with core-shell structure as high-
2
4
L
DOI: 10.1021/acs.inorgchem.9b00627
Inorg. Chem. XXXX, XXX, XXX−XXX