High-Temperature Electrochemical Performance Enhancement of Lithium-Rich Layered Oxides by Surface Modification

Lithium-rich layered oxides (LLOs) are one of the attractive cathodes for high-energy lithium-ion batteries (LIBs). However, their rate performance and cycling stability, especially at high temperatures, are still limited for practical applications. Herein, combining surface modification with a spinel structure and oxygen vacancy and introduction an electronic conductor of multidimensional carbon, the electrochemical performance of LLOs at high temperatures has been significantly improved. At an operation temperature of 55 °C, the modified LLOs can deliver a high rate capacity of 223.3 mAh g–1 at 5C and a capacity retention of 78.5% at 1C after 100 cycles. An investigation into the pristine and modified LLOs using high-temperature in situ electrochemical X-ray diffraction has revealed that the latter has better structural stability during the electrochemical cycling process and exhibits a smaller cell volume variation of 1.99% compared to 3.47% of the former. This work can provide an effective way to solve the poor cycle stability and rate capability of LLOs and also introduce the high-temperature in situ electrochemical X-ray diffraction technique for structure evolution investigations of other battery systems.