Computational Study of Strain-Engineered Black/Blue Phosphorene Nanosheets as Anchoring and Catalytic Materials for Lithium–Sulfur and Lithium–Selenium Batteries

Despite the prosperous prospects of lithium–sulfur (Li–S) and lithium–selenium (Li–Se) batteries, the severe shuttle effect and slow redox reactions greatly inhibited their further development. Designing efficient anchoring and catalytic cathode host materials is an important strategy to meet the above challenges. Strain engineering can be used to regulate the electrochemical properties of electrode materials to promote their performance for batteries. In the present work, the feasibility and efficiency of strain-modulated black/blue phosphorene nanosheets as cathode host materials for Li–S and Li–Se batteries have been investigated by density functional theory (DFT) calculations. The ab initio molecular dynamics simulation and phonon spectral calculations confirm the thermal and kinetic stability of the strained phosphorene. The tensile strain has an unfavorable effect on the anchoring performance of phosphorene toward polysulfides or polyseleniums, while the compressive strain can strengthen their immobilization ability, with the −7% strain guaranteeing the black/blue phosphorene nanosheets to be the qualified anchoring materials to effectively suppress the shuttle effect of Li–S and Li–Se batteries. Furthermore, the compressive strain (optimal value: −7%) can promote the bidirectional electrocatalytic activity of phosphorene for the sulfur/selenium reduction reaction (SRR/SeRR) and Li₂S/Li₂Se oxidation. Combined with the enhanced electronic conductivity of phosphorene under −7% compressive strain and the fast Li ion diffusion, the presented merits demonstrate that the black/blue phosphorene nanosheets under appropriate strain can be promising anchoring and catalytic materials, and strain engineering is a useful strategy for improving the electrochemical performance of Li–S/Li–Se batteries.