MXene‐Coupled Sandwich‐Like Polyaniline as Dual Conductive Electrode for Flexible All‐Solid‐State and Ionic‐liquid‐Based Supercapacitors with Superior Energy Density

Abstract

Abstract2D conducting materials (2DCMs), such as graphene, coordination polymers including 2D‐metal‐organic frameworks, conducting organic polymer nanosheets, metal sheets, and their composites are promising candidates for energy storage and conversion applications. Rational design and preparation of 2DCMs usually involve specific templates (soft or hard) that often sacrifice conductivity and negatively impact the electrochemical charge storage performance. In this work, 2D MXene is used as the conductive substrate yielding sandwich‐like MXene‐polyaniline hybrids (MX@PANIs) for high‐performance supercapacitors (SCs) operating in aqueous, solid‐state, and ionic‐liquid‐based safe electrolytes. The MX@PANI‐based flexible all‐solid‐state SC using PVA‐H2SO4 delivers an excellent energy density of 28.6 W h kg–1 at 0.2 kW kg–1. Importantly, the synergistic effect of constituents in MX@PANI in ionic liquid (EMITFSI) electrolyte exhibits an impressive energy density performance of 139 W h kg–1 at a power density of 1.66 kW kg–1, exceeding most of the reported PANI and MXene‐based SCs. This piece of work offers a feasible solution to create the next generation energy‐storage devices using novel 2D hybrid nanocomposites working in safer electrolytes for high‐performance SCs.