Electrochemical reconstruction from mixed-phase nickel niobium to Ni-rich LixNb2O5 towards fast charging Li-ion battery

Fast charging capability is a crucial aspect of next-generation ion battery development, but the ion diffusion rate in existing anode materials is limited. It is necessary to design an anode material with a suitable host structure to effectively promote the ion transport rate. In this study, a novel nickel niobate (Ni4Nb2O9) is proposed as an anode material for lithium-ion battery, and a mixed-phase structure consisting of NiNb2O6 and Ni4Nb2O9 (MNNO) is creatively constructed based on component engineering. The phase interfaces within the mix phases prove instrumental in facilitating the transmission of lithium ions and electrons. Notably, Ni-rich Ni4Nb2O9 enhances the precipitation of metallic Ni nanoparticles during electrochemical reconstruction, thereby effectively improving the electrical conductivity of the electrode material and enhancing its rate performance. The composite delivers an impressive specific capacity of 216 mAh g-1 at 1C and maintains 98.9 % capacity retention after 1000 cycles at 10C. Moreover, the assembled full-cell with NCM811 as a cathode exhibits 173.1 mAh g-1 at current densities of 1C. Therefore, the mixed-phase nickel niobates demonstrate good adaptability and stability in a wide voltage range (0.005-3 V), presenting a new approach for designing high-performance and fast charging lithium battery anodes.