10.1002/cssc.201802290
ChemSusChem
FULL PAPER
ether) to afford 7.16 g (67%) of pure product as an orange powder; 13C
NMR (125 MHz, CDCl3, δ): 168.3.
Cathode Fabrication and Galvanostatic Test: Slurries of the tetrazines,
carbon black (Timcal Super P), and PVDF (Sigma Aldrich) in
dimethylformamide (DMF) were prepared in a vial with a weight ratio of
4:4:2. For the DPT/CMK-3 composite electrodes, slurries were mixed
with the DPT/CMK-3 composite materials, carbon black, and PVDF in a
weight ratio of 8:1:1. The slurries were stirred overnight at room
temperature and then spread on aluminum foils by doctor blading. The
electrodes were dried at 25 °C for 8 h in a vacuum oven and punched
into circular discs with a diameter of 14 mm. Coin type CR2032 (Hohsen)
cells were assembled with the cathodes, a Li-metal anode, and a
polypropylene separator (Celgard 2400) in an Ar-filled glove box (Korea
Kiyon KK-011-AS) in which moisture and oxygen levels were tightly
regulated under 0.5 ppm. The galvanostatic discharge/charge tests of the
coin cells at different current densities (the C-rate of the tetrazine
electrodes were calculated by their theoretical specific capacity values)
were performed on a battery cycler (Wonatech WBCS3000L) at 30 °C.
Synthesis of 3,6-dimethoxy-1,2,4,5-tetrazine (DMT): DCT (0.50 g, 3.31
mmol) was dissolved in 8 mL of anhydrous methanol. At 25 °C, Na2CO3
(1.75 g, 16.55 mmol) was added dropwise to the solution, and MgSO4
was added for solvent dryness. The reaction mixture was stirred at 65 °C.
After removal of the solvent, the crude product was purified by silica gel
column chromatography using 1:1 (v/v) dichloromethane/hexane eluent
mixture to give 145 mg of red solid (30.8%). 1H NMR (300 MHz, CDCl3,
δ) 4.26 (s, 6H), 13C NMR (125 MHz, CDCl3, δ) 166.58 (C of the tetrazine
ring), 56.87 (C of the methoxy).
Synthesis of 3-chloro-6-ethoxy-1,2,4,5-tetrazine (CET). DCT (0.50 g,
3.31 mmol) was dissolved in 15 mL of anhydrous dichloromethane, and
added successively 0.2 mL (1.2 eq.) ethanol and 0.4 g (1 eq) collidine,
and stirred about 1 h at room temperature. CET was purified by
chromatography (Pet. Ether 3/Dichloromethane 1) and 0.46g of powder
was recovered (81%). 1H NMR (300 MHz, CDCl3, δ) 4.74 (q, 2H), 1.59 (t,
3H), 13C NMR (125 MHz, CDCl3, δ) 166.75, 164.39, 67.17, 14.34.
Acknowledgements
This work was supported by (1) the Presidential Post-doc.
Fellowship Program through the National Research Foundation
of Korea (NRF) funded by the Ministry of Education
(2016R1A6A3A04008134[RIAM0417-20180002]); (2) National
R&D Program through the National Research Foundation of
Korea(NRF) funded by the Ministry of Science & ICT (No.
2017M3A7B4041699).
Ex-situ XPS: The electrodes were prepared at different states of charge
(as-prepared, discharged to 2 V, and recharged to 2.7 V (DPT) or 3.5 V
(DCT)), respectively. To prevent exposure to air, all samples were moved
to Ar-filled glove box before opening the coin cells. After disassembling
the coin cells, the electrodes were washed several times with DOL and
DME to remove the residual electrolytes. Subsequently, the residual
solvents were removed from the electrode in a vacuum chamber. Then,
the electrodes were sealed in Ar-filled vials. XPS measurements were
conducted with
a ULVAC-PHI 5000 VersaProbe equipped with a
Keywords: s-tetrazine • organic electrode materials • lithium-ion
secondary battery • organic battery • CMK-3
microfocus monochromated Al Kα (1486.6 eV) X-ray. All samples were
analyzed at an electron take-off angle of 45 degree, measured from the
surface plane. Binding energies were referenced to the C–C bond of the
C 1s region at 284.5 eV.
[1]
J. B. Goodenough, K. S. Park, J. Am. Chem. Soc. 2013, 135, 1167-
1176.
[2]
[3]
[4]
[5]
T. Ohzuku, R. J. Brodd, J. Power Sources 2007, 174, 449-456.
M. S. Whittingham, Chem. Rev. 2014, 114, 11414-11443.
D. Larcher, J. M. Tarascon, Nat. Chem. 2015, 7, 19-29.
Y. Liang, Z. Chen, Y. Jing, Y. Rong, A. Facchetti, Y. Yao, J. Am. Chem.
Soc. 2015, 137, 4956-4959.
Theoretical Calculation: All density functional theory (DFT) calculations
were carried out in the gas phase using the Gaussian 09 quantum-
chemical package. The geometry optimizations were performed using
Becke-Lee-Yang-Parr (B3LYP) functionals and the 6-31G+(d,p) basis set.
Vibrational frequency calculations were performed for the obtained
structures at the same level to confirm the stable minima.
[6]
[7]
[8]
[9]
T. B. Schon, B. T. McAllister, P. F. Li, D. S. Seferos, Chem. Soc. Rev.
2016, 45, 6345-6404.
M. Armand, S. Grugeon, H. Vezin, S. Laruelle, P. Ribiere, P. Poizot, J.
M. Tarascon, Nat Mater 2009, 8, 120-125.
Electrochemical Measurement: Cyclic voltammetry (CV) was performed
on a Princeton Applied Research Model 273a using a three-electrode
beaker cell with 0.01 M AgNO3/Ag as a reference electrode, a glassy
carbon disc (diameter = 3 mm) as a working electrode, and a platinum
M. Yao, H. Senoh, S.I. Yamazaki, Z. Siroma, T. Sakai, K. Yasuda, J.
Power Sources 2010, 195, 8336-8340.
Z. Song, H. Zhou, Energy Environ. Sci. 2013, 6, 2280.
wire as
a counter electrode, respectively. The redox potential of
reference electrode was calibrated using ferrocenium/ferrocene (Fc+/Fc)
as an internal standard. The tetrazine solutions were made to be 5 × 10-3
M in CH3CN except for DPT (3 × 10-3 M) due to its lower solubility than
the other tetrazines in CH3CN, and 0.1 M NBu4PF6 was used as a
supporting electrolyte.
[10] B. Häupler, A. Wild, U. S. Schubert, Adv. Energy Mater. 2015, 5,
1402034.
[11] N. Oyama, T. Tatsuma, T. Sato, T. Sotomura, Nature 1995, 373, 598-
600.
[12] S.R. Deng, L.B. Kong, G.Q. Hu, T. Wu, D. Li, Y.H. Zhou, Z.Y. Li,
Electrochim. Acta 2006, 51, 2589-2593.
[13] P. Novák, K. Müller, K. S. V. Santhanam, O. Haas, Chem. Rev. 1997,
97, 207-282.
Fabrication of DPT/CMK-3 Composites: The DPT/CMK3 composites
were prepared by a simple method. DPT and CMK-3 (BET1000, 99%,
ACS Material) were mixed in dimethylformamide (DMF) with various
mixing ratios (DPT:CMK-3 = 1:2, 1:1, and 2:1 by weight, respectively).
After ultrasonication for 1 h, the solvent of the mixed solutions was slowly
evaporated overnight under the ambient condition. Then, the mixtures
[14] Y. Wu, R. Zeng, J. Nan, D. Shu, Y. Qiu, S.L. Chou, Adv. Energy Mater.
2017, 7, 1700278.
[15] M. Zhou, J. Qian, X. Ai, H. Yang, Adv. Mater. 2011, 23, 4913-4917.
[16] P. J. Nigrey, D. MacInnes, D. P. Nairns, A. G. MacDiarmid, A. J.
Heeger, J. Electrochem. Soc. 1981, 128, 1651-1654.
[17] W. Choi, S. Ohtani, K. Oyaizu, H. Nishide, K. E. Geckeler, Adv. Mater.
2011, 23, 4440-4443.
were placed in
completely.
a vacuum oven to remove the residual solvents
[18] O. Kenichi, N. Hiroyuki, Adv. Mater. 2009, 21, 2339-2344.
[19] Q. Zhao, Y. Lu, J. Chen, Adv. Energy Mater. 2017, 7, 1601792.
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