Flexible, temperature-tolerant supercapacitor based on Ti3C2Tx MXene in ionic liquid gel electrolyte

Abstract

Due to its unique structure and performance, Ti₃C₂T_x has been widely investigated as an electrode material for flexible energy storage devices using hydrogel as a solid electrolyte. The composition and structure of hydrogels determine their poor performance at high temperatures and there is little research on MXene flexible devices at high temperature. In this work, we designed a method for preparing capacitors with Ti₃C₂T_x as the electrode material and ionic liquid as the electrolyte. By leveraging the high permeability of ionic polymer solution, a seamless electrode-electrolyte interface is constructed. The device can achieve a maximum capacitance of 173.8 mF cm⁻² at a 5 mV s⁻¹ scan rate, with a maximum specific energy density and power density of 96.57 μWh cm⁻² and 1.74 mW cm⁻², respectively. The capacitor retains 89.5 % of its initial capacitance after 20,000 cycles, demonstrating excellent cycle stability. Importantly, the supercapacitor can operate at 100 °C with a specific capacitance of 278.66 mF cm⁻². In addition, the designed device can retains 100 % or more of its capacitance even after 1000 cycles of 180° bending，demonstrating robust mechanical performance. This work provides a reference for studying the application of MXene in high-temperature flexible supercapacitor.