Defect-enhanced performance of a 3D graphene anode in a lithium-ion battery

Morphological defects were generated in an undoped 3D graphene structure via the involvement of a ZnO and Mg(OH)2 intermediate nanostructure layer placed between two layers of vapor-deposited graphene. Once the intermediate layer was etched, the 3D graphene lost support and shrank; during this process many morphological defects were formed. The electrochemical performance of the derived defective graphene utilized as the anode of a lithium (Li)-ion battery was significantly improved from ~382 mAh g−1 to ~2204 mAh g−1 at 0.5 A g−1 compared to normal 3D graphene. The derived defective graphene exhibited an initial capacity of 1009 mAh g−1 and retention of 83% at 4 A g−1 for 500 cycles, and ~330 mAh g−1 at a high rate of 20 A g−1. Complicated defects such as wrinkles, pores, and particles formed during the etching of the intermediate layer, were considered to contribute to the improvement of the electrochemical performance.