NiGa₂O₄/rGO Composite as Long-Cycle-Life Anode Material for Lithium-Ion Batteries

This work reports a novel Ga-based material, NiGa 2 O 4, which is typically used as a photocatalyst for water splitting, as an anode for Li-ion battery with a long cycle life. High-surface-area reduced graphene oxide (rGO) has been used as the conductive substrate to avoid the aggregation of NiGa 2 O 4 nanoparticles (NPs). Because the size and shape of NiGa 2 O 4 are very sensitive to the pH of the precursor, ethylene glycol has been employed as the solvent, as well as the reduction agent to reduce GO, to avoid using extra surfactants and also to avoid the variation of pH of the precursor. The obtained NiGa 2 O 4 /rGO composite possesses high capacity and long cycle life (2000 cycles, 2 A/g), with NiGa 2 O 4 NPs around 3–4 nm that are uniformly distributed on the rGO surface. Full cell performance with LiCoO 2 as cathode has also been studied, with the average loss of 0.04% per cycle after 100 cycles (C/2 of LiCoO 2 ). The long cycle life of the composite was ascribed to the self-healing feature of Ga 0 formed during charging.