Electrostatically Sprayed Reduced Graphene Oxide-Carbon Nanotubes Electrodes for Lithium-Ion Capacitors

Abstract

Lithium-ion capacitors (LICs) comprising capacitor-type and battery-type electrodes are promising electrochemical energy storage systems to effectively combine the merits of lithium-ion batteries (LIBs) and electrochemical capacitors (ECs). It is expected that the energy density of LICs can be improved by utilizing electrodes that are capable of providing high specific capacity. Herein, we demonstrate a graphene-based LIC with reduced graphene oxide-carbon nanotube (rGO-CNT) film as capacitor-type electrode and pre-lithiated rGO-CNT film as battery-type electrode using 1 M LiPF6 in EC: EMC electrolyte. The rGO-CNT was prepared by electrostatic spray deposition (ESD), which offers advantages, such as simultaneous reduction and binder-free deposition of GO on a current collector and facile morphology control. The rGO-CNT shows high specific capacity and good cyclability as both capacitor-type and battery-type electrode materials. The rGO-CNT//lithiated rGO-CNT LIC delivered energy densities as high as 114.5 Wh Kg−1 and maximum power density of 2569 W kg−1. This indicates the promising potential of the ESD approach for the facile fabrication of graphene-based electrodes for high performance LICs.