Binder‐Free High‐Performance MXene Supercapacitors Fabricated by a Simple Electrospray Deposition Technique

Abstract

AbstractIn this work, an electrospray deposition (ESD) technique is applied to fabricate binder‐free porous 2D MXene (Ti3C2Tx) electrodes for supercapacitor applications. As a result of the crumpling of MXene flakes induced by the capillary force during drying, a porous structure is formed between MXene flakes within the electrode which leads to the formation of channels for rapid ion‐diffusion. Together with binder‐free networks of highly electrical conductive MXene sheets, these ion diffusion channels greatly improve the rate capability of the electrospray MXene electrode. Cyclic voltammetry measurements show that micron‐thickness electrodes retain their capacitive rectangular‐shaped curves even at a very high scan rate of 10 000 mV s−1 in KOH electrolyte. A specific capacitance as high as 400 F g−1 is also recorded in H2SO4 electrolyte and this high specific capacitance maintains 85% of its value when the scan rate is increased to 1000 mV s−1. Furthermore, the electrospray MXene electrode shows good cycle stability in H2SO4 without a binder. About 90% of the capacitance is maintained after 10 000 charge–discharge cycles at a current density of 15 A g−1. All of these results show that the ESD MXene electrodes are a promising candidate for supercapacitor applications that require both high capacitance and enhanced rate capability.