Zn-doped Cr2O3 oxides boosted the electrochemical performance of aqueous hybrid supercapacitor

Aqueous hybrid supercapacitors (AHSCs) have emerged as a promising choice for advanced energy storage systems in the next generations. It is primarily due to their exceptional characteristics, such as superior power density, non-flammability, and environmental compatibility. However, compared to non-aqueous super capacitors, the small working potential windows and less cycle stability are their key challenges to solve. A facile method was used to synthesize Zn-doped Cr2O3 supported on carbon cloth (CC) as a binder-free electrode for AHSCs and denoted as ZnCr2O4@CC. According to the experimental findings, the ZnCr2O4@CC material possesses a rapid charge transfer. As a result, the ZnCr2O4@CC electrode showed a remarkable charge storage performance with dominant charge storage by capacitive type (68.4 % at 10 mVs- 1). Further, the ZnCr2O4@CC electrode exhibits a maximum capacitance of 374 Fg- 1 at 1 Ag-1 and outperforms its counterparts (194 Fg- 1 for Cr2O3 and 60.78 Fg-1 for ZnO). After 10,000 cycles, the ZnCr2O4@CC electrode still shows 98.1 % of its initial capacitance, demonstrating its potential for practical applications. The AHSC device also constructed using ZnCr2O4@CC as a cathode and activated carbon (AC) as an anode with 1 M KOH as an electrolyte (ZnCr2O4@CC//AC-AHSC). The AHSC device exhibits an excellent capacitance retention of 96.43 % after 10,000 cycles. Further, the AHSC shows a superb energy density of 26.2 Whkg-1 at a power density of 800.6 Wk -1 g. The current work describes a new strategy for the production of next-generation aqueous hybrid supercapacitors with exceptional electrochemical performance.