Dual-working-electrode photoelectrochemical techniques are implemented to characterize semiconductor–catalyst–solution interfaces in protected n-Si photoanodes in situ for the first time.

Rechargeable aqueous zinc-ion batteries (AZIBs) are considered for emerging cutting-edge energy storage technologies as an alternative to the existing nonaqueous lithium-ion batteries (LIBs) owing to their inimitable advantages of low-cost materials, high safety, high abundance, and environmental friendliness. Nevertheless, the key challenges of the AZIBs are mainly due to the development of cathode (positive electrode) materials. Here, we report the synthesis of vanadium-based oxides on twodimensional (2D) vanadium carbide MXene (V 2 O x @V 2 CT x ) that can serve as an efficient cathode material for AZIBs. The vanadium-based oxides could be formed during the high-temperature etching method and by the electrochemical cyclic process. The prepared V 2 O x @V 2 CT x electrodes can deliver an ideal rate performance with an average reversible capacity of about 304 to 84 mAh g −1 at current densities ranging from 0.05 to 2 A g −1 , respectively. The obtained results can be comparable to the well-known cathode materials reported for the ZIBs. Advancing from the characteristic, stable 2D layered structures, V 2 O x @V 2 CT x electrodes could exhibit an improved cycling life with the capacity retention of 81.6% at a rate of 1 A g −1 for about 200 cycles in 1 M ZnSO 4 electrolyte. The prepared MXene as cathode materials could further pave the way for the development of the advanced zinc ion storage systems.

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