Plane-Selective Coating of Li2SnO3 on Li[NixCo1-x]O2 for High Power Li ion Batteries.

Abstract

Interphase engineering is becoming increasingly important in improving the electrochemical performance of cathode materials for rechargeable batteries, including Li ion, Li metal, and all-solid-state batteries, because irreversible surface reactions, such as electrolyte decomposition, and transition metal dissolution, constitute one of these batteries' failure modes. In this connection, various surface-engineered cathode materials have been investigated to improve interfacial properties. No synthesis methods, however, have considered a plane-selective surface modification of cathode materials. Herein, we introduce the basal-plane-selective coating of Li2SnO3 on layered Li[NixCo1-x]O2 (x = 0 and 0.5) using the concept of the thermal phase segregation of Sn-doped Li[NixCo1-x]O2 due to the solubility variation of Sn in Li[NixCo1-x]O2 with respect to temperature. The plane-selective surface modification enables the formation of Li2SnO3 nanolayers on only the Li[NixCo1-x]O2 basal plane without hindering the charge transfer of Li+ ions. As a result, the vertical heterostructure of Li[NixCo1-x]O2-Li2SnO3 core-shells show promising electrochemical performance.