Advanced pseudocapacitive performances of a Ti3C2Tx-ZnOHF/ZnO nanocomposite for energy storage applications

The growing demand for efficient and high-performance energy storage systems is driving the exploration of novel materials and composites. Traditional electrode materials often face limitations in terms of energy and power densities. This paper demonstrates novel spray-coated cathode electrode system composed of Ti3C2Tx MXene and zinc hydroxy fluoride/zinc oxide (ZnOHF/ZnO) nanostars (NSs) for energy storage applications in a neutral pH electrolyte (1M Na2SO4), thus avoiding corrosion problems related to water splitting reactions. Optimized Ti3C2Tx-NSs electrodes exhibited superior specific capacitance, achieving 236 F g−1 at 5 mV s−1 in cyclic voltammetry (CV) and 139 F g−1 at 5 mV s−1 in galvanostatic charge-discharge (GCD) measurements, which is superior to bare Ti3C2Tx (115 F g−1 at 0.5 A g−1) and bare NSs (108 F g−1 at 0.5 F g−1) electrodes, used as reference. Additionally, an asymmetric Ti3C2Tx||Ti3C2Tx-NSs supercapacitor device achieved a specific capacitance of 147 F g−1 at 0.5 A g−1, an energy density Ed ~ 46 W h kg−1 at a power density Pd ~ 875 W kg−1, and the highest Pd ~ 16650 W kg−1 at Ed ~ 14 W h kg−1. These findings demonstrate that ZnO NSs combined with delaminated Ti3C2Tx MXene, hold a significant promise for efficient energy storage applications, leveraging the synergy between double-layer capacitance and pseudocapacitive effects.