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

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.