Lithium and Sodium Storage on Graphitic Carbon Nitride

We present results from density functional theory calculations of the lithium adsorption onto 2D graphitic carbon nitride membranes, C₃N₄ and C₆N₈ and bulk C₃N₄. We find that lithium adsorbs preferentially over the triangular pores with a high adsorption energy. We also find that lithium adsorption severely distorts the membrane and bulk material. The lithium mainly interacts with the pyridinic nitrogen in the material, which enables a large lithium uptake. However, the pyridinic nitrogen is also responsible for the instability of the material. We also present experimental results on the charge and discharge capacities of C₆N₈. These mirror the theoretical prediction that the material shows a high lithium uptake which is, however, irreversible