13453-79-7Relevant articles and documents
Role of Local and Electronic Structural Changes with Partially Anion substitution Lithium Manganese Spinel Oxides on Their Electrochemical Properties: X-ray Absorption Spectroscopy Study
Okumura, Toyoki,Fukutsuka, Tomokazu,Matsumoto, Keisuke,Orikasa, Yuki,Arai, Hajime,Ogumi, Zempachi,Uchimoto, Yoshiharu
, p. 9752 - 9764 (2011)
The electronic and local structures of partially anion-substituted lithium manganese spinel oxides as positive electrodes for lithium-ion batteries were investigated using X-ray absorption spectroscopy (XAS). LiMn 1.8Li0.1Ni0.1O4-ηF η (η = 0, 0.018, 0.036, 0.055, 0.073, 0.110, 0.180) were synthesized by the reaction between LiMn1.8Li0.1Ni 0.1O4 and NH4HF2. The shift of the absorption edge energy in the XANES spectra represented the valence change of Mn ion with the substitution of the low valent cation as Li+, Ni 2+, or F- anion. The local structural change at each compound with the amount of a Jahn-Teller Mn3+ ion could be observed by EXAFS spectra. The discharge capacity of the tested electrode was in the order of LiMn2O4 > LiMn1.8Li 0.1Ni0.1O4-ηFη (η = 0.036) > LiMn1.8Li0.1Ni0.1O4 while the cycleability was in the order of LiMn1.8Li 0.1Ni0.1O4-ηFη (η = 0.036) ≈ LiMn1.8Li0.1Ni0.1O4 > LiMn2O4. It was clarified that LiMn1.8Li 0.1Ni0.1O4-ηFη has a good cycleability because of the anion doping effect and simultaneously shows acceptable rechargeable capacity because of the large amount of the Jahn-Teller Mn3+ ions in the pristine material.
Effect of Zn doping on the performance of LiMnPO4 cathode for lithium ion batteries
Fang, Haisheng,Yi, Huihua,Hu, Chenglin,Yang, Bin,Yao, Yaochun,Ma, Wenhui,Dai, Yongnian
, p. 266 - 269 (2012)
In this work, effect of Zn doping on the performance of LiMnPO4 is revisited. Samples of pure and Zn-doped LiMnPO4 are synthesized by a new solid-state method, and their structure, morphology and electrochemical behavior are characterized and compared. The results reveal that a small amount of Zn doping (2 at.%) is highly beneficial for the performance of LiMnPO 4 due to the reduced charge transfer resistance, the increased lithium ion diffusion and phase conversion, but this effect is remarkably traded off at a high level of Zn doping (10at.%). Compared with LiMnPO4, LiMn0.98Zn0.02PO4 has a much higher capacity and a much better rate capability. After 2 at.% Zn doping, the discharge capacity increases from 101 to 139 mAhg-1 at 0.1 C and 56 to 105 mAhg-1 at 2 C.
On the knowledge of oxides A[MO4]: On LiMnO4, KMnO4, RbMnO4, CsMnO4 as well as RbIO4, CsIO4. (-What does the crystal structure of . . . mean? -)
Hoppe,Fischer,Schneider
, p. 1135 - 1142 (2008/10/08)
These investigations confirm again that, sufficient purity, symmetry and lack of disorder etc. of investigated single crystals provided: the structure of a solid is characterized only if a) lattice constants are determined precisely by powder data; b) a couple of single crystals is sufficiently investigated by film data; c) the quantitative comparison of crystal structures of a chemical series like A[MnO4] with another one like A2[SO4] alone enables one to estimate the quality of different structural investigations of the same material. d) The crystal structure of a solid is still non-existent.
Cathodic behavior of alkali manganese oxides from permanganate
Chen, Rongji,Whittingham, M. Stanley
, p. L64-L67 (2008/10/08)
The reaction of potassium, sodium, and lithium permanganate in water at 170°C leads directly to potassium, sodium, and lithium manganese dioxides, AyMnO · nH2O, with a R3m rhombohedral structure. These crystalline layered structures after dehydration readily and reversibly react with lithium through an intercalation mechanism. The capacity for lithium is a function of the alkali ion present, and the larger potassium ion maintains the capacity best. For lithium there is a tendency to convert to the spinel structure which leads to loss of capacity.
