High-Temperature\nSupercapacitors Based on MXene with\nUltrahigh Volumetric Capacitance

Abstract

Currently, MXene-based supercapacitors (MSCs) have been\nwidely\nstudied due to their good flexibility and excellent electrochemical\nperformance. At present, the application of supercapacitors is more\nand more extensive, which requires them to face various complex environments.\nHowever, MSCs applied under high-temperature conditions have not been\nreported. In this paper, the MXene–V₂O₅–polyaniline (MVP) ternary composite material is used as the\nelectrode material, and sulfonated polybenzimidazole (SPBI) is used\nas the solid electrolyte to design high-temperature MSCs for the first\ntime. The preparation of MVP is achieved by introducing V₂O₅ into the MXene layer and loading polyaniline (PANI)\non its surface, which not only greatly improves the capacitance performance\nof the electrode but also ensures its stability at a high temperature.\nThe capacitance value of the MVP electrode was as high as 3180 mF\ncm^–3 (880 F g^–1), with excellent\nmechanical properties and increased flexibility at the same time.\nFurthermore, the assembled supercapacitor has a high energy density\nof 79.2 Wh L^–1 (22.1 Wh kg^–1).\nMoreover, its capacitance value can reach 985.3 mF cm^–3 (276 F g^–1) at 120 °C. This work provides\nan efficient design of an energy storage device that can be used for\nhigh-temperature applications.