Spontaneous electrochemical reconstruction of NiNb2O6@C for High-Rate Lithium-Ion batteries

Niobium oxides are widely active in the arena of lithium-ion batteries due to their distinctive structure and rapid charging capability, nevertheless facing the serious challenge from their inherently low electrical conductivity. Herein, a molten salt method is proposed to prepare nickel niobate (NiNb2O6) anode materials for lithium-ion batteries, and a carbon coating derived from mesophase pitch is fabricated to construct NiNb2O6@C composites. Importantly, NiNb2O6@C undergoes spontaneous electrochemical reconstruction to generate metallic Ni and amorphous Nb2O5 during the initial charge/discharge cycle. The presence of the outer carbon layer not only serves as a uniform conductive coating to improve the conductivity and thereby deliver superior rate performance, but also effectively inhibits the stripping of Ni0 to guarantee a great cycling stability. The synergistic effects of the dual conductive interfaces, consisting of the carbon layer and the Mott-Schottky heterojunction between amorphous Nb2O5 and metallic Ni, culminate in exceptional electrochemical performance. Specifically, NiNb2O6@C-10% delivers impressive specific capacity of 436.3 mAh g−1 at 0.5C and conspicuous cycling stability, maintaining 86.3% capacity retention after 800 cycles at 10C. This work underscores the substantial potential of nickel niobate anode materials in advancing the development of next-generation lithium-ion batteries.