Rational designing NiVO@CoNi-MOF heterostructures on activated carbon cloth for high-performance asymmetric supercapacitors and oxygen evolution reaction.

Binder-free self-supported carbon cloth electrode provides novel strategies for the preparation of MOFs, effectively improving the conductivity and promoting charge transfer. Combining MOFs with vanadate to form a unique heterogeneous structure provides a large specific surface area and more active sites, further enhancing the kinetics of MOFs. Herein, a self-supported carbon cloth electrode is prepared by in-situ growth of CoNi-MOFs on activated carbon cloth (AC) and coating with NiVO. The heterostructure increases the specific surface area and exposes more active sites to promote the adsorption and diffusion of ions, thus enhancing the kinetic activity and optimizing charge storage behavior. As expected, the NiVO@CoNi-MOF/AC exhibits a specific capacitance of up to 19.20 F/cm at 1 mA/cm. The asymmetric supercapacitors (ASCs) assembled by NiVO@CoNi-MOF/AC and annealed activated carbon cloth achieve an energy density of 1.27 mWh/cm at a power density of 4 mW/cm and have a capacitance retention of 96.43 % after 10,000 cycles. In addition, the NiVO@CoNi-MOF/AC as electrocatalyst has an overpotential of 370 mV at 10 mA/cm and a Tafel slope of 208 mV dec, demonstrating remarkable electrocatalytic oxygen evolution reaction performance. These unique heterostructures endow the electrode with more electrochemical selectivity and provide new key insights for designing multifunctional materials.