Strategy of constructing unsaturated bond on hexagonal pore MXene through titanium vacancy defects realizes antioxidant stable storage of potassium-ions in neutral aqueous system

In order to solve the key problem that MXene is easy to oxidize in aqueous environment, resulting in poor long cycle stability of energy storage devices. In this work, a defect control strategy was used to induce the formation of unsaturated coordination bonds on the surface of titanium vacancy defect hexagonal pore MXene. Under the premise of ensuring the storage of potassium-ions with high energy density, hexagonal pore MXene has achieved the effect of oxidation resistance and long cycle stability in neutral aqueous supercapacitors. According to the experiment and theoretical calculation, the optimum adsorption position of potassium-ions in hexagonal pore MXene was determined, and the adsorption energy of MXene for potassium-ions was reduced. The conductivity and transmission rate of potassium-ions were improved, showing excellent electrochemical energy storage performance. The antioxidant mechanism of hexagonal pore MXene was also revealed. This provides a new approach for MXene's environmentally friendly oxidation resistant stable electrochemical energy storage.