N-Doped Graphene Quantum Dots Supported by Carbon Nanotubes Grown on Carbon Clothes for Lithium Storage

Abstract

Graphite has been widely used as an anode material for commercial lithium-ion battery applications because of its excellent stability and low cost. However, graphite-based anodes need to improve the energy storage capacities to meet the increasing power demands of next-generation technologies. Here, we have developed a class of novel and flexible electrode materials that consist of N-doped graphene quantum dots supported by carbon nanotubes grown on carbon cloth (denoted as CC/CNT@N-GQD). Such architecture synergistically combines the advantages of three dimensions/one dimension substrates and zero dimension N-GQDs. It greatly improves the electron/ion transport kinetics of N-GQDs, resulting in attractive electrochemical performance in terms of high reversible capacity and excellent rate capability. Moreover, the annealing temperature plays an important role in the control of N-doping types of CC/CNT@N-GQD. CC/CNT@N-GQD anodes annealed at 500 °C have a high content of pyridinic N, exhibiting a very excellent rate capability and cycling stability, as exemplified by a capacity of 2.88 mAh cm−2 at 4 mA cm−2 and a reversible capacity of 3.63 mAh cm−2 after 150 cycles at 0.19 mA cm−2.