Ti3C2Tx (MXene)-wrapped V2O5/Fe2O3 composites for enhanced-performance supercapacitors

Abstract

Among transition-metal oxides, vanadium oxides and iron oxides have attracted much attention for electrochemical energy storage devices due to their high theoretical specific capacities and multiple variable valence states of V and Fe. However, the poor conductivity of both oxides leads to poor rate performance and high charge transfer resistance between the electrolyte and electrodes. Herein, Ti₃C₂T_x-wrapped V₂O₅/Fe₂O₃ (VFO) composites were designed and prepared for achieving enhanced electrochemical performance. The VFO composites on carbon cloth were synthesized by a hydrothermal method, and the optimized VFO electrode exhibited a capacitance of 435.2 mF cm⁻² at a current density of 2 mA cm⁻². By wrapping with Ti₃C₂T_x, the areal capacitance of the VFO composite electrode was greatly enhanced up to 1150.82 mF cm⁻² at a current density of 2 mA cm⁻². The enhanced electrochemical performance of the Ti₃C₂T_x@VFO composites is mainly attributed to the synergistic effects of the improved conductivity and diminished collapse and falling off of VFO during the charging and discharging processes. For practical application, asymmetrical supercapacitor (ASC) MnO₂//Ti₃C₂T_x@VFO devices were constructed. The device exhibited a maximum energy density of 0.17 mW h cm⁻² at a power density of 1.26 mW cm⁻² with a capacitance retention of 74.92% after 5000 cycles. This work indicates the potential application of various oxides in high-performance supercapacitors by modification with MXenes.