First principles prediction of two-dimensional tungsten carbide (W2C) monolayer and its Li storage capability

First-principles calculations are performed to study the electronic properties and Li ion storage capabilities of the proposed two-dimensional (2D) W2C monolayer. After ensuring its dynamical and thermal stabilities, we found that the Li atom is strongly bound to the W2C monolayer. The metallic character of both pristine and doped W2C ensures a good electronic conduction that is essential for an optimal anode material. Low migration energy barrier is predicted as small as 45 meV for Li, which results in the very fast diffusion of Li atom on W2C. We found the storage capacity is 259 mA h g−1. The calculated average voltage of 0.55 V for Li makes W2C attractive for low charging voltage applications.