Preparation of three-dimensional free-standing nano-LiFePO4/graphene composite for high performance lithium ion battery

Abstract

Electric vehicles and high-power electrical appliances demand batteries of a high rate discharge performance, but it is still a challenge due to large electric resistance for very fast charge transport. In this paper, a nano-LiFePO₄/graphene (G/LiFePO₄) composite is synthesized by one-pot in situ hydrothermal method. The LiFePO₄ nanoparticles are wrapped by graphene sheets on a three-dimensional (3D) free-standing graphene foam obtained from the self-assembling of graphene oxide, which is used as a highly conductive current collector. The as-prepared G/LiFePO₄ composite has a 3D conductive network and can be directly used for the cathode without any conductive carbon black, binder or aluminum current collector. The electrochemical measurements show it has excellent rate performance, the 10C-rate specific discharge capacity is 115 mA h g⁻¹. The overall electrochemical performance from this 3D self-assembly free-standing structure is superior in the similar reported system.