Flexible Ti3C2Tx MXene Film Coupled with Defect-Rich MoO3 Spacer-Contributor toward High-Performance Wearable Energy Storage

Abstract

MXene film-derived flexible supercapacitors have shown great application foreground for wearable electronics, but the capacitive characteristics, especially when faced with mechanical deformations, are not satisfactory. Herein, a new kind of flexible electrode, MX/D-MoO₃, is developed by using Ti₃C₂T_x MXene film (MX) and defect-rich MoO₃ (D-MoO₃) as the “main body” and “spacer-contributor”, respectively. Results indicate that, with D-MoO₃ intercalation, notably enlarged layer spacing of Ti₃C₂T_x nanosheets and boosted electrochemical active sites are fulfilled, which have facilitated wondrous property increases of 342% and 239% when compared to raw MX and MX/MoO₃, respectively. Particularly, MX/D-MoO₃-60 has a high specific capacitance of 2734.3 mF cm⁻² at 1 mA cm⁻², which surpasses most of the counterparts reported thus far. The MX/D-MoO₃-60-based all-solid-state supercapacitor presents the largest energy density of 96.3 µWh cm⁻² at 205.9 µW cm⁻² and an outstanding power density of 1871.4 µW cm⁻² at 18.6 µWh cm⁻². Meanwhile, impressive stability with capacitance retention of 91.8% after 5 000 cycles and great mechanical flexibility with capacitance retention of 90.3% under bending angles from 0 to 180° are also exhibited. The superior properties and facile preparation endow MX/D-MoO₃-60 with promising applications in wearable energy storage.