Multi-shelled LiMn1.95Co0.05O4 cages with a tunable Mn oxidation state for ultra-high lithium storage

Abstract

Superior electrochemical performance of LiMn₂O₄ is considered to be one of the most important properties for lithium-ion batteries (LIBs). This paper presents an extremely high performance cathode material, multi-shelled LiMn_1.95Co_0.05O₄ cages, which are created using a sucrose template. A small amount of Co substitution uniformly in a bulk material not only tunes Mn³⁺ in the minority with bulk stability improving, but can also accommodate specific capacity. In addition, the unique caged structure enhances Li⁺ diffusion and electrolyte penetration, leading to an outstanding rate capability. The as-synthesized cathode material exhibits a very high capacity of 154.4 mA h g⁻¹, and retains a high value of 136.7 mA h g⁻¹ after 500 cycles. The present work investigated the combined effect of a tunable average Mn oxidation state and unique multi-shelled cages in a controllable aerosol process.