Large-scale preparation of cobalt niobate/reduced graphene oxide composite materials for high-performance lithium-ion battery anodes

In the field of nanotechnology, the electrodes have received widespread attention as they are a key factor affecting the performance of lithium-ion batteries (LIBs). In this study, a cobalt niobate/reduced graphene oxide composite material (CoNb2O6/rGO) was prepared using ball-milling-assisted high-temperature calcination and used as an anode for LIBs for the first time. We studied the effects of calcination temperature on the morphology, structure, and electrochemical performance of CoNb2O6/rGO. The experimental results showed that rGO wrapped around the sphere-like CoNb2O6 particles of nanoscale size. With increasing calcination temperature, the crystallinity of CoNb2O6 increased, while the number of defects in rGO decreased, thus improving the conductivity of CoNb2O6/rGO. CoNb2O6 exhibits a higher specific capacity—the discharge capacity of CoNb2O6/rGO-900 is 540.9 mAh/g initially and 457.3 mAh/g after 200 cycles—than that exhibited by graphite (370 mAh/g) at low current densities (0.1 A/g). Furthermore, CoNb2O6 exhibits excellent cyclic stability—the discharge capacity is 130.6 mAh/g initially and 102.8 mAh/g after 4000 cycles, with a capacity retention rate of 78.7%—under a high current density of 5 A/g. The preparation method is a solid-phase technique suitable for large-scale preparation and industrial production. •Cobalt niobate/reduced graphene oxide composite material (CoNb2O6/rGO) is designed.•The application of CoNb2O6/rGO as anode of lithium ion battery is studied for the first time.•Graphene can inhibit particle growth, prevent agglomeration and improve electrical conductivity.•The solid-phase preparation method is beneficial to large-scale production and industrial application.•CoNb2O6/rGO has a higher specific capacity than graphite at low current densities (0.1 A g−1).•CoNb2O6/rGO has excellent cyclic stability under high current density (5 A g−1).