Graphene-Assisted Chemical Stabilization of Liquid Metal Nano Droplets for Liquid Metal Based Energy Storage

TL;DR

This paper introduces a graphene oxide coating technique for liquid metal nano droplets, significantly enhancing their stability and energy storage capacity in various pH environments, enabling advanced liquid metal-based supercapacitors.

Contribution

It presents a novel graphene oxide coating method for liquid metal droplets that improves stability and electrochemical performance in energy storage devices.

Findings

GO coating enhances stability in acidic and alkaline environments

Energy capacity increases over 10 times with GO coating

Areal capacitance reaches 20.02 mF/cm² with optimized coating

Abstract

Energy storage devices with liquid_metal electrodes have attracted interest in recent years due to their potential for mechanical resilience, self_healing, dendrite_free operation, and fast reaction kinetics. Gallium alloys like Eutectic Gallium Indium (EGaIn) are appealing due to their low melting point and high theoretical specific capacity. However, EGaIn electrodes are unstable in highly alkaline electrolytes due to Gallium oxide dissolution. In this letter, this bottleneck is addressed by introducing chemically stable films in which nanoscale droplets of EGaIn are coated with trace amounts of graphene oxide (GO). It is demonstrated that a GO to EGaIn weight ratio as low as 0.01 provides enough protection for a thin film formed by GO EGaIn nanocomposite against significantly acidic or alkaline environments (pH 1-14). It is shown that GO coating significantly enhances the surface stability in such environments, thus improving the energy storage capacity by over 10x. Microstructural analysis confirms GO EGaIn composite stability and enhanced electrochemical performance. Utilizing this, a thin film supercapacitor is fabricated. Results indicate that when coating the EGaIn with GO to EGaIn ratio of 0.001 the areal capacitance improves by 10 times, reaching 20.02 mF cm_2. This breakthrough paves the way for advanced liquid metal-based thin film electrodes, promising significant improvements in energy storage applications.