Theoretical prediction of 2D biphenylene as a potential anchoring material for lithium–sulfur batteries

Abstract

Searching for good anchoring materials that can suppress the shuttle effect is critical to large-scale commercialization of lithium–sulfur (Li–S) batteries. In this work, the adsorption behavior of lithium polysulfides (LiPSs, such as S₈ and Li₂S_n, n = 1, 2, 4, 6, and 8), the sulfur reduction reaction (SRR), the decomposition processes of Li₂S and the diffusion behavior of Li atoms on intrinsic and doped 2D biphenylene (BIP) are systematically investigated by employing the first-principles calculation method. Calculations show that the adsorption energies of LiPSs on the electrolyte (DOL and DME) are smaller than those on the intrinsic/B doped BIP. The moderate anchoring strength (0.8–2.0 eV) between LiPSs and the BIP can effectively suppress the shuttle effect. Moreover, the Gibbs free energy barrier for SRR is 0.72/0.64 eV on intrinsic/B doped BIP. The dissociation energy barrier of Li₂S on intrinsic/B doped BIP is 1.35 eV, while the diffusion energy barrier of Li atoms on intrinsic/B doped BIP is 0.18 eV/0.30 eV. Lower energy barriers are conducive to enhancing the discharging and charging efficiency. Therefore, intrinsic and B doped BIP are predicted as good anchoring materials for Li–S batteries.