Electrochemical performances and structure characteristic of LiMn2O4-xYx (Y=F, Cl, Br) compounds
(School of Metallurgical Science and Engineering, Central South University,
Changsha 410083, China)
Changsha 410083, China)
Abstract: Spinel LiMn2O4-xYx(Y=F, Cl, Br) compounds were prepared by solid-state reaction and the electrochemically galvanostatic charge-discharge cycles were performed using as-prepared compounds as cathode material. The influence of halogens on their lattice constants and the relation of electrochemical properties and their lattice constants were investigated. It is concluded that when the lattice constants are smaller than that of LiMn2O4, the reversible capacity fade is suppressed and the initial capacity sacrifice is observed. When the content of fluorine is 0.05, the lattice constant of LiMn2O3.95F0.05 is larger than that of LiMn2O4, the initial capacity is improved. An efficient method was found to control the lattice constants of LiMn2O4 through the addition of halogen, and to improve the electrochemical performance of LiMn2O4. The LiMn2O3.95F0.05 shows excellent electrochemical charge-discharge performance, with high initial capacity of 143mAh/g and nearly no capacity loss after 116 cycles.
Key words: spinel LiMn2O4-xYx; lattice constant; cathode materials; lithium-ion rechargeable battery; halogen