Hierarchical porous onion-shaped LiMn 2 O 4 as ultrahigh-rate cathode material for lithium ion batteries

Spinel LiMn 2 O 4 is a widely utilized cathode material for Li-ion batteries. However, its applications are limited by its poor energy density and power density. Herein, a novel hierarchical porous onion-like LiMn 2 O 4 (LMO) was prepared to shorten the Li + diffusion pathway with the presence of uniform pores and nanosized primary particles. The growth mechanism of the porous onion-like LiMn 2 O 4 was analyzed to control the morphology and the crystal structure so that it forms a polyhedral crystal structure with reduced Mn dissolution. In addition, graphene was added to the cathode (LiMn 2 O 4 /graphene) to enhance the electronic conductivity. The synthesized LiMn 2 O 4 /graphene exhibited an ultrahigh-rate performance of 110.4 mAh·g –1 at 50 C and an outstanding energy density at a high power density, maintaining 379.4 Wh·kg –1 at 25,293 W·kg –1 . Besides, it shows durable stability, with only 0.02% decrease in the capacity per cycle at 10 C. Furthermore, the (LiMn 2 O 4 /graphene)/graphite full-cell exhibited a high discharge capacity. This work provides a promising method for the preparation of outstanding, integrated cathodes for potential applications in lithium ion batteries.