Holey reduced graphene oxide/carbon nanotube/LiMn0.7Fe0.3PO4 composite cathode for high-performance lithium batteries

Abstract

Graphene has attracted considerable attention as the conductive agent for lithium batteries by providing a superior interfacial contact. However, the wrapping of active materials by the large area of graphene sheets may hinder the transportation of Li+ between active particles and electrolyte, especially at a high charge/discharge rates. Herein, holey graphene oxide (h-GO), which is made by a green wet ball-milling of GO in one step without using any catalysts or chemicals, is combined with carbon nanotubes (CNTs) and LiMn0.7Fe0.3PO4 (LMFP) to make a composite cathode for lithium batteries. Results show that after the electrochemical reduction, the LMFP cathode with h-GO/CNT shows remarkedly improved electrochemical performances due to the facilitated Li+ transport pathway, compared to that with conventional GO/CNT. For example, LMFP/h-GO/CNT composite cathode can achieve a discharge capacity of 112 mAh g−1 when discharged at 20 C, while LMFP electrode with conventional GO/CNT only shows a discharge capacity of 35 mAh g−1. This study provides a new approach for fabricating holey graphene and can open up new possibilities for applications on power sources.