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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.

To illustrate the effect of microwave radiation on the morphologies and electrochemical properties electrode materials, Ni-rich oxide LiNi0.85Co0.05Mn0.1O2was identified and prepared from the corresponding precursors synthesized under different reaction conditions. The results suggest that the resultant LiNi0.85Co0.05Mn0.1O2morphology controllably depends on its corresponding synthetic method, which will affect its electrochemical property accordingly. The electrode material from microwave-assisted co-precipitation followed by a hydrothermal modification (NCM-WH) possesses a pure α-NaFeO2phase and regular spheroidal morphology with a proper size over 10 μm, which exhibits more excellent discharge capacity of ca. 150 mAh g−1after 200 cycles and better capacity retention of 88.3% than those from microwave-assisted co-precipitation method (NCM-W) or normal co-precipitation method (NCM-N) only. The improved electrochemical properties are confirmed from their ordered phase structure, regular spheroidal morphology and high tap density, which results in lower Li/Ni cation mixing, faster solid-state ion diffusion, higher electrochemical reversibility and better structure stability during the long-tern cycles.