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

The Li-rich layered cathode material Li_1.165Mn_0.501Ni_0.167Co_0.167O₂ with 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 Li_1.165Mn_0.501Ni_0.167Co_0.167O₂ composite 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^?1 at 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 ^?1 is still obtained after 100 cycles. Furthermore, the diffusion coefficients of Li⁺ investigated by the cyclic voltammetry technique are approximately 10^?15–10^?14 cm² s^?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.