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

Abstract

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 (CoNb 2 O 6 /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 CoNb 2 O 6 /rGO. The experimental results showed that rGO wrapped around the sphere-like CoNb 2 O 6 particles of nanoscale size. With increasing calcination temperature, the crystallinity of CoNb 2 O 6 increased, while the number of defects in rGO decreased, thus improving the conductivity of CoNb 2 O 6 /rGO. CoNb 2 O 6 exhibits a higher specific capacity—the discharge capacity of CoNb 2 O 6 /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, CoNb 2 O 6 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 (CoNb 2 O 6 /rGO) is designed. • The application of CoNb 2 O 6 /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. • CoNb 2 O 6 /rGO has a higher specific capacity than graphite at low current densities (0.1 A g −1 ). • CoNb 2 O 6 /rGO has excellent cyclic stability under high current density (5 A g −1 ).