Ultrathin 2D Metallenes for Energy Storage: A Myth or Reality?

Abstract

Rapid depletion of fossil fuels and increased energy scarcity paved the way to utilize electrochemical energy storage devices such as batteries and supercapacitors for the power delivery applications. The electrode-active materials play a crucial role in determining the electrochemical performance in these devices. Ultrathin two-dimensional (2D) materials have attracted great research interest in the recent past due to their unique properties such as large surface area, lightweight, good electronic conductivity, high strength, good chemical and electrochemical properties, etc. to name a few. Metallenes are emerging class of 2D materials with atomic thickness and consisting of metals or alloys with a well-controlled surface atomic arrangement. 2D metallenes are used as electrode-active materials in rechargeable batteries and supercapacitors in the literature. Since metallenes consist of melallic 2D sheets, the charge storage is limited by the electrode kinetics and also more prone to corrosion when used in electrolytes, this motivated us to examine the truth behind these fascinating materials. This article unveils the various types of metallenes available, their synthesis methods and the mechanism of charge storage in rechargeable batteries and supercapacitors for a better clarification.