An engineered self-supported electrocatalytic cathode and dendrite-free composite anode based on 3D double-carbon hosts for advanced Li–SeS2 batteries

Abstract

SeS₂ is a promising cathode material that combines the advantages of S and Se for lithium storage, but a similar shuttle effect of intermediate lithium polysulfides/polyselenides in SeS₂ cathodes and the dendrite growth in Li metal anodes also pose a challenge for Li–SeS₂ battery application. Herein, a 3D double-carbon conductive scaffold consisting of CNT-wrapped nitrogen-rich carbon foam (CF@CNTs) is designed to rationally serve as a universal host for engineering both SeS₂ cathodes and Li metal anodes along with achieving reliable electrochemistry simultaneously. Experimental and theoretical results reveal that SeS₂ can be well hosted into the internal voids of CF@CNTs with implanted polar CoS₂, forming a self-supported electrocatalytic cathode with high rate capability, long cycling life, and considerable areal capacity (>6.5 mA h cm⁻²) at an ultrahigh SeS₂ loading of 12.3 mg cm⁻² due to the synergetic trapping–catalytic-conversion effect of both polysulfides and polyselenides. Besides, the 3D meso-/macro-porous framework together with rich lithiophilic N heteroatoms make CF@CNTs an ideal Li host material effective in regulating metallic Li plating and suppressing Li dendrite growth in the anodes. Combining the cathodic and anodic improvements further achieves remarkably enhanced cyclability in full Li–SeS₂ cells with stable coulombic efficiency, providing new opportunities for high-energy batteries.