Nickel Niobate Anodes for High Rate Lithium‐Ion Batteries

Fast charging is one of the key requirements for next‐generation lithium‐ion batteries, however, lithium‐ion diffusion rates of typical electrode materials are limited. Nanosizing of active electrode material is a common strategy to increase the effective lithium‐ion diffusion transport rate, but it also decreases the volumetric energy/power density and stability of the battery. In this work, nickel niobate NiNb2O6 is demonstrated for the first time as a new intrinsic high‐rate anode material for lithium‐ion batteries without the requirement of realizing nano‐architectures. The NiNb2O6 host crystal structure exhibits only a single type of channel for lithium‐ion intercalation and can be fully lithiated with a capacity of about 244 mAh g−1 at low current densities. Interestingly, a high diffusion coefficient of 10−12 cm2 s−1 at 300 K enables fast (dis)charging at high current densities resulting in high capacities of 140 and 50 mAh g−1 for 10 and 100C respectively. The minimal volume change during lithiation is the origin of the stable reversible lithiation process in NiNb2O6 and leads to 81% capacity retention after 20 000 cycles at 100C. Finally, full cell systems against LiFePO4 and Li[Ni0.8Co0.1Mn0.1]O2 (NCM811) cathodes demonstrate the promising energy storage performance of nickel niobate anodes in practical battery devices. Nickel niobate NiNb2O6 is a new intrinsic high‐rate anode material and can be fully lithiated with a capacity of about 244 mAh g−1, while a high diffusion coefficient of 10−12 cm2 s−1 enables fast (dis)charging with capacities of 140 and 50 mAh g−1, for 10 and 100 C respectively, with 81% capacity retention after 20 000 cycles at 100 C.