Triggering cationic/anionic hybrid redox stabilizes high-temperature Li-rich cathodes materials via three-in-one strategy

Efficiently advancing lithium -ion batteries toward high energy density entails overcoming challenges in Li-rich layered oxides, including severe voltage and capacity fading, irreversible oxygen escape and compromised thermal robustness due to the uncontrollable oxygen anionic redox (OAR). Herein, a three-in-one modification strategy, aim at strengthening the reversibility of OAR and structural integrity of MnO6 octahedron, is rationally introduced on Li1.2Mn0.53Ni0.20Co0.07O2 cathode through a universal H3BO3-treatment. Through the introduction of oxygen vacancies and gradient B -doping, the energy level of unhybridized O 2p states is decreased to narrow the band energy gap with transition metal (TM) band, which triggers cationic/anionic hybrid redox at high voltage, thereby stabilizing the peroxo-like (O2)n- species and hindering irreversible oxygen escape, while the lithium borate nano-coating serves to mitigate side reactions, particularly during charging at elevated temperatures. As a result, the modulated cathode exhibits notable capacity retention of 96.3 % after 500 cycles at 1 C with limited voltage fading rate (1.73 mV per cycle) and even stable cyclic performance at high temperature (60 degrees C). This approach provides an effective and straightforward method to tackle the voltage decay and capacity fading of high-energy Li-rich layered cathode materials.