Systematic comparison of hollow and solid Co3V2O8 micro-pencils as advanced anode materials for lithium ion batteries

Cobalt vanadates have been demonstrated as superior anode candidates for lithium ion batteries (LIBs) owing to their unique advantages, such as superb specific capacity, low operating potential, and excellent cycling stability. Among the cobalt vanadates, Co3V2O8 manifests tremendous potential of commercialization because of their controllable particle size and morphology. In this study, we readily synthesized both hollow and solid Co3V2O8 micro-pencils and thoroughly compared their electrochemical properties. Employed as anode for LIBs, the hollow Co3V2O8 exhibited much higher initial specific capacity than the solid ones (∼1200 mAhg−1 vs. ∼680 mAhg−1). When tested at 1000 mAg−1, the hollow Co3V2O8 displayed superior reversible capacity over the solid ones (∼650 mAhg−1 vs. ∼450 mAhg−1 after 300 cycles), benefiting from the hollow architecture. Moreover, the hollow micro-pencils showed better rate performance, with outstanding stability and capacity loss when higher current density was applied. The comparative study demonstrated the hollow Co3V2O8 is more efficient than the solid ones for LIB anodes. Based on the comparison on pure micro-pencils, further approach (e.g. graphene coating) can be exploited for superior performance towards ultimate application in lithium-ion batteries.