In-situ formation of uniform V2O5 nanocuboid from V2C MXene as electrodes for capacitive deionization with higher structural stability and ion diffusion ability

Capacitive desalination (CDI) has aroused much attention due to its advantages of low energy consumption and environmental compatibility. However, typical CDI processes display limited efficiency. In this work, one-dimensional V 2 O 5 with nanocuboid structure was prepared with MXenes(V 2 C) precursor for the first time, which has high adsorption capacity, structure stability and fast ion diffusion ability. The as-synthesized V 2 O 5 electrode achieved a salt adsorption capacity(SAC) of 55.2 mg NaCl g −1 V 2 O 5 under optimized conditions with a constant current density of 30 mA g −1 , a voltage range from −0.6 to 1.2 V, and an initial solution of 500 mg L −1 NaCl. Furthermore, from the comprehensive analysis of mechanism, due to the high conductivity and low charge transfer resistance of V 2 O 5 electrode, it reduces the energy loss of the resistance during desalination. A particularly low energy consumption of 0.27 kWh kg −1 -NaCl is reached when the operation is carried out successfully at low voltage range, indicating the advantages of energy saving and high efficiency. Therefore, V 2 O 5 is an attractive and promising electrode material, which exhibits the potential of pseudocapacitive materials with certain structure for practical CDI application in future and inspires us to have a deep insight into the effect of morphology on the properties.