Vertically pillared V2CTx/Ti3C2Tx flexible films for high-performance supercapacitors

Abstract

2D MXenes have attracted extensive attention for energy storage applications owing to their high electronic conductivity, excellent redox activity, and remarkable mechanical property. Nevertheless, they still suffer from sluggish ion kinetics caused by layer restacking. Herein, flexible V2CTx/Ti3C2Tx composite films have been successfully assembled. The delaminated Ti3C2Tx matrix guarantees the predominant electronic conductivity and mechanical stability of the flexible electrode. Meanwhile, V2CTx spacers embedded in Ti3C2Tx layers efficiently restrain their self-restacking and consequently result in enriched ion channels for electrolyte ion accessibility. Benefiting from this elaborately designed vertical-liked pillar structure, the V2CTx/Ti3C2Tx electrode exhibits a maximum gravimetric capacitance of 365 F g−1 at 1 A g−1, and outstanding cycling stability without capacitance loss after 10,000 cycles. Moreover, the assembled symmetric supercapacitor shows a high energy density of 5.4 mWh g−1 at a power density of 357.8 mW g−1. This work may demonstrate an efficient approach for combining the respective advantages of binary or ternary MXenes with different metal elements and morphologies for efficient energy storage.