Vertically Pillared V ₂CT _x/Ti ₃C ₂T _x 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 V₂CT_x/Ti₃C₂T_x composite films have been successfully assembled. The delaminated Ti3C2Tx matrix guarantees the predominant electronic conductivity and mechanical stability of the flexible electrode. Meanwhile, V₂CT_x spacers embedded in Ti₃C₂T_x 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 V₂CT_x/Ti₃C₂T_x electrode exhibits a maximum gravimetric capacitance of 356 F g^-1 at 2 mV s^-1, and outstanding cycling stability without capacitance loss after 10000 cycles. Moreover, the assembled symmetric supercapacitor shows a high energy density of 7.33 mWh g^-1 at a power density of 289.02 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.

Keywords: MXene, Supercapacitor, Pillared Supporting, Composite Film, Flexible Electrode