Nb Doping Reduces the Primary Particle Size of the Li-Rich Cathode

Lithium-rich materials exhibit promising potential as commercial lithium-ion battery cathodes, offering a specific energy of 900 Wh.kg −1 , surpassing other commercial cathode materials by more than 20%. However, challenges such as low initial efficiency, poor conductivity, and subpar cycling performance, along with rapid voltage decay, have impeded their commercialization. In this study, we propose a niobium-doping technique for lithium-rich materials. By controlling particle size during high-temperature sintering, niobium facilitates the production of highly crystalline, small-grain lithium-rich materials. This approach achieves both high capacity and long cycle life. Specifically, at 0.5 C, the pouch cell demonstrates a maximum specific capacity of 230.2 mAh.g −1 , retaining 85.2% after 500 cycles, with a voltage drop of less than 0.3 mV/cycle. Additionally, we investigated the mechanism of niobium in suppressing particle growth through doping with elements of varying M-O bond strengths, obtaining systematic data. A new effect of niobium on lithium-rich cathodes was discovered. The primary particle size of lithium-rich cathodes can be modulated during the sintering stage by doping with appropriate substances. The 0.5% Nb-doped sample has a specific capacity of 230.2 mAh g −1 , compared to the pristine sample’s 216.4 mAh g −1 at 0.5 C.