Implanting heterogeneous Ni2P/CoP catalysts in MOF–derived carbon arrays with multifunctional catalytic sites for Li–SeS2 batteries

Abstract

SeS 2 possesses the combined merits of S and Se with considerable capacity and high electronic conductivity, but is still hindered by a shuttle effect of lithium polysulfides/polyselenides and sluggish conversion kinetics. Herein, high–efficiency heterogeneous Ni 2 P/CoP catalysts implanted into MOF–derived carbon arrays (Ni 2 P/CoP@NC) are developed to simultaneous immobilize polysulfides/polyselenides and regulate their conversion. The Ni 2 P/CoP catalysts with hollow and hierarchical structures extremely expose abundant catalytic and adsorption sites for LiPS/LiPSe conversion reaction. Meanwhile, the strong chemical binding of Ni 2 P/CoP towards LiPSs/LiPSes through Ni–S, Ni–Se, Co–S and Li–P bonds favors for the regulation of polysulfide/polyselenide conversion. The DFT calculation results corroborate the heterogeneous Ni 2 P/CoP interface provides depressed lithium–ion diffusion barriers to promote the polysulfide/polyselenide conversion kinetics. Benefiting from abundant catalytic and adsorption sites, strong chemical binding towards LiPSs/LiPSes and depressed lithium–ion diffusion barriers, the Ni 2 P/CoP@NC catalysts enable considerable specific capacities, superior rate performance and stable cycling performance for Li–SeS 2 batteries. • Hollow heterogeneous Ni 2 P/CoP nanoparticles implanted in carbon arrays are developed for SeS 2 immobilizers. • Ni 2 P/CoP heterostructures chemically immobilize LiPSs/LiPSes through Ni-S, Ni-Se, Co-S and Li-P bonds. • A reduced diffusion barrier of Li 2 S on Ni 2 P/CoP enables efficient catalytic conversion. • SeS 2 @Ni 2 P/CoP@NC cathode exhibits superior rate performance and stable cycling performance.