A Facile <scp>Li₂TiO₃</scp> Surface Modification to Improve the Structure Stability and Electrochemical Performance of Full Concentration Gradient Li‐Rich Oxides

Abstract

Full concentration gradient lithium‐rich layered oxides are catching lots of interest as the next generation cathode for lithium‐ion batteries due to their high discharge voltage, reduced voltage decay and enhanced rate performance, whereas the high lithium residues on its surface impairs the structure stability and long‐term cycle performance. Herein, a facile multifunctional surface modification method is implemented to eliminate surface lithium residues of full concentration gradient lithium‐rich layered oxides by a wet chemistry reaction with tetrabutyl titanate and the post‐annealing process. It realizes not only a stable Li 2 TiO 3 coating layer with 3D diffusion channels for fast Li + ions transfer, but also dopes partial Ti 4+ ions into the sub‐surface region of full concentration gradient lithium‐rich layered oxides to further strengthen its crystal structure. Consequently, the modified full concentration gradient lithium‐rich layered oxides exhibit improved structure stability, elevated thermal stability with decomposition temperature from 289.57 °C to 321.72 °C, and enhanced cycle performance (205.1 mAh g −1 after 150 cycles) with slowed voltage drop (1.67 mV per cycle). This work proposes a facile and integrated modification method to enhance the comprehensive performance of full concentration gradient lithium‐rich layered oxides, which can facilitate its practical application for developing higher energy density lithium‐ion batteries.