Polymer microsphere-assisted synthesis of lithium-rich cathode with improved electrochemical performance

The Li-rich layered cathode material Li1.165Mn0.501Ni0.167Co0.167O2with porous structure has been successfully synthesized through a facile co-precipitation approach followed with a high-temperature calcination treatment, adopting polymer microsphere (PSA) as a template and conductive agent. The PSA-assisted Li1.165Mn0.501Ni0.167Co0.167O2composite exhibits remarkably improved cycling stability and rate capability compared with the bare composite. It delivers a high initial discharge capacity of 267.0 mA h g-1at 0.1 C (1 C=250 mA g-1) between 2.0 V and 4.65 V. A discharge capacity of 214.9 mA h g-1is still obtained after 100 cycles. Furthermore, the diffusion coefficients of Li+investigated by the cyclic voltammetry technique are approximately 10-15-10-14cm2s-1. Such outstanding performance is mainly ascribed to: on one hand, the carbon residue of PSA after being calcined at high temperature contributes to enhance the electronic conductivity of the electrode and alleviates the volume changes during the Li+-insertion/extraction, leading to an improved rate capability; on the other hand, the unique porous structure and small particle size are conductive to increase the exposed electrochemical active surface, shorten Li+diffusion distance and thus enhance the lithium storage capacity.