A “nano jungle” like interlayer with CoP2/Ni2P heterojunctions for trapping-catalyzing lithium polysulfides in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries face challenges such as the shuttle effect of lithium polysulfides (LiPSs) and sluggish reaction kinetics. Herein, a freestanding interlayer is constructed by in-situ growing carbon nanotubes (CNTs) encapsulated with CoP 2 /Ni 2 P heterostructured nanoparticles on the surface of waste viscose derived carbon fibers (Ni-Co-P@CNT/CF). The surface of the carbon fibers exhibits a “nano jungle” like morphology. The interconnected carbon fibers framework ensures efficient electron transport. While the tentacle-like Ni-Co-P@CNT structure facilitates the efficient capture of dissolved LiPSs and promotes their liquid-solid reaction. The built-in electric field (BIEF) at the heterointerface facilitates electron transfer, promotes the Li + diffusion and lowers the energy barriers of sulfur species conversion, which enhances LiPSs chemical adsorption and accelerates their conversion kinetics. Electrochemical tests demonstrate its outstanding performance. The cell delivers an impressive reversible capacity of 994 mAh g −1 after 300 cycles at 0.2C with a low decay rate of 0.049% per cycle. When the current density increases to 1.0C, the cell retains 580 mAh g −1 after 450 cycles. Even under high sulfur loadings (3.9 mg cm −2 ), the interlayer can still maintain stable catalytic activity.