Three-dimensional porous radical polymer/reduced graphene oxide composite with two-electron redox reactions as high-performance cathode for lithium-ion batteries

Abstract

Organic cathode materials, especially stable radical polymers, have been considered as ideal substitutes to inorganic cathode for rechargeable lithium batteries (LIBs) due to their fast electron transfer kinetics, tunable electrochemical properties, facile solution processing and environmental sustainability. Unfortunately, unsatisfied electronic conductivity of polymers leads to poor practical capacity, low utilization efficiency, and hinder their application for LIBs. In this work, a three-dimensional porous electrode composed by poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) and reduced graphene oxide (PTMA/rGO) is prepared via a simple dissolution-assembly-depositing method. Since the 3D porous structure effectively promotes the electrolytes penetration and facilitates electron conduction pathways, satisfactorily, the PTMA/rGO electrode shows an obvious two-electron redox reactions and delivers the highest reversible capacity of 153 mA h g−1 at 20 mA g−1 with an ultrahigh utilization efficiency of 98.8%, which is much higher than that of PTMA/CB electrode prepared by the traditional physical mixing method (104 mA h g−1, utilization efficiency of 66.1%). Meanwhile, the PTMA/rGO electrode also exhibits excellent rate performance and cycle stability. This kind of high performance PTMA/rGO electrode with simple preparation method provides a broad application prospect of the next generation of high performance LIBs based on organic electrode.