Synthesis and electrochemical characteristics of oxysulfide spinel material for lithium secondary batteries

Oxysulfide spinel LiMn₂O_3.98S_0.02 powders with monodispersed, and highly homogeneous particles were synthesized by a sol-gel method using an aqueous solution of metal acetates and sulfide containing glycolic acid as a chelating agent. The oxysulfide spinel, LiMn₂O_3.98S_0.02 electrode initially delivers 80 mAh g⁻¹, steadily increases during cycling, and reaches 99 mAh g⁻¹ at the 20th cycle. The substitution of a small amount S for O in LiMn₂O₄ spinel helps to maintain structural integrity during cycling, which then overcomes the Jahn–Teller distortion in the spinel Mn phase in the 3 V region.