Facile preparation of regular truncated octahedral LiMn2O4 cathode with high rate cyclability and stability for Li-ion batteries

Spinel LiMn2O4, as a mainstream commercial cathode material for lithium-ion batteries, is still suffered from severe capacity fading caused by Mn dissolution and Jahn-Teller distortion during the cycle process, which can be solved by developing selectively exposed crystal planes. Herein, a perfect monocrystal LiMn2O4 with regular truncated octahedral structure has been synthesized via a facile and low-cost carbon template sol-gel method. The phase composition and morphology of LiMn2O4 can be regulated by carbon template content, ranging from irregular micro-aggregates to nanoporous network structure composed of truncated nano-octahedrons with high crystallinity. The high crystallinity suppresses Jahn-Teller distortion and the large presence of {111} surfaces inhibit Mn dissolution can both improve its cycle stability, the unique nanoporous network structure facilitates shortening the Li+ diffusion path and the truncated {100} and {110} surfaces promote Li+ diffusion can increase the discharge capacity and rate capability. Accordingly, the as-obtained LMO-0.5 sample achieves remarkable discharge specific capacity (135.8 mA h/g at 0.1 C), excellent rate capability (91.2 mA h/g even at 20 C) and prominent cycle stability (a capacity retention of 91.7 % after 2000 cycles at 20 C), which will be an ideal cathode material for developing long-lifespan lithium-ion batteries.