Multifunctional polymer/C hybrid coating enables durable cycling of Li-rich layered oxide cathodes

Lithium-rich layered oxides (LROs) are promising cathode materials for high-energy lithium-ion batteries because of their high specific capacity and energy density. However, oxygen release, stress accumulation, and interfacial degradation during high-voltage cycling still hinder their practical application. Here, an aqueous-processed polyimide/carbon hybrid coating is designed to stabilize LROs. The coating is constructed from a polyimide and a conductive carbon network composed of carbon nanotubes and Super P. The hybrid coating layer provides surface protection, while the carbon components form continuous electron-transport pathways. During post-treatment, mild carbothermal reactions further induce surface oxygen vacancies, which help regulate oxygen-related surface reactions. The modified cathode delivers discharge capacities of 246.6 mAh g−1 at 1 C, with a capacity retention of 94.9% after 200 cycles at 25 °C. This work provides a practical aqueous interfacial coating strategy for improving the durability of high-energy LROs.