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

Ebenezer Adelowo,Amin Baboukani,Chunlei Wang,Chunhui Chen

doi:10.3390/c4020031

Ebenezer Adelowo, Amin Baboukani + Show 2 more

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https://doi.org/10.3390/c4020031

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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.

Highlights

The rapid expansion of the global market for consumer electronic and electric vehicles requires high performance energy storage units, especially with high energy density and high power density, while still retaining good cyclability [1,2,3]
Lithium ion capacitor (LIC) represents a stand-alone energy storage system that is capable of combining the positive attributes of lithium-ion batteries (LIBs) and electrochemical capacitors (ECs) to provide relatively high energy density, high power density, and good cyclability [6,7]
Capacitor-type electrode that is capable of fast charge-discharge kinetics and high surface area, high specific capacity is a key requirement for the high energy performance of LICs [3,8,9]

Summary

Introduction

The rapid expansion of the global market for consumer electronic and electric vehicles requires high performance energy storage units, especially with high energy density and high power density, while still retaining good cyclability [1,2,3]. ECs are based on non-faradaic electrochemical double layer capacitance (EDLC) storage mechanism or pseudocapacitive faradaic reactions, enabling higher power density, fast charge, and discharge rate, as well as longer cyclability than LIBs, they exhibit relatively lower energy density. Lithium ion capacitor (LIC) represents a stand-alone energy storage system that is capable of combining the positive attributes of LIB and EC to provide relatively high energy density, high power density, and good cyclability [6,7]. Capacitor-type electrode that is capable of fast charge-discharge kinetics and high surface area, high specific capacity is a key requirement for the high energy performance of LICs [3,8,9]. It is expected that LIC energy density can be improved by utilizing electrodes that are capable of offering higher specific capacity in place of traditional activated carbon and graphite

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