Analyses of vanadium carbide as an anode for post-lithium batteries

Today, lithium batteries dominate the market of rechargeable batteries, but lithium production is expensive and environmentally detrimental. Given increasing demand and rising costs, the search for alternative rechargeable batteries is critical. This work investigates the performance of a promising 2D MXene anode material, vanadium carbide (V₂C), for use in metal-ion batteries. We compare the properties of four promising alternative metal-ions (Na, Mg, Al, and Ag) with lithium (Li) using DFT. The comparison revealed that Na and Ag perform comparably to Li, with a respective OCV of 0.66–1.32 V and 0.91–1.23 V, with respective theoretical specific capacities of 627 mA h g⁻¹ and 967 mA h g⁻¹, compared to an OCV of 0.75–1.00 V and a capacity of 967 mA h g⁻¹ for Li. The diffusive barrier of Na is exceptionally low, 0.007 eV, and the barrier for Ag is 0.07 eV, while the barrier for Li is 0.02 eV. The Mg- and Al-ion batteries perform with a very high maximum charging capacity, 1883 mA h g⁻¹ and 2823 mA h g⁻¹ respectively, and a slightly lower OCV range of 0.39–0.45 V and 0.22–0.45 V respectively. Due to the good capacity, high OCV and low diffusive barriers of the ions, V₂C anodes are ideal for post-lithium metal-ion battery applications.