Carbon Nitride Monolayers as Efficient Immobilizers toward Lithium Selenides: Potential Applications in Lithium-Selenium Batteries

The low cost, high energy density, and nontoxic nature have made lithium-selenium batteries (LiSeBs) a promising option for large-scale energy storage applications. However, the issue of capacity loss during consecutive charge/discharge cycles has put a serious question mark on the commercialization of LiSeBs. In a quest to suppress the issue of capacity loss due to the dissolution of active lithium polyselenides (Li2Sen, n = 1-8) into the electrolyte, the so-called shuttle effect, we have employed first-principles density functional theory calculations to study the anchoring properties of two carbon nitrides monolayers, namely, nitrogenated holey graphene (C2N) and carbon nitride (C3N). We find that the presence of nitrogen (N) atoms, in both C2N and C3N, enable them to bind Li2Sen clusters stronger than that of graphene. We further discover that the anchoring properties of C2N (-2.03 to -3.82 eV) are stronger than that of C3N (-1.21 to -1.30 eV) due to higher concentrations of N atoms and relatively bigger pore size in the former than the later. In addition to the appropriate bindings, improved conductivities upon the adsorption Li2Sen further reinforce the promise of C2N and C3N as potential anchoring materials for LiSeBs. We believe that our computational results would pave the way toward the experimental synthesis of efficient anchoring materials based on the studied systems.