Interfacial Build-In Electric Field Unlocking Hetero-Architectured CoO-Co3O4 Nanotubes Toward High-Performance Li-S Batteries

Abstract

The sluggish redox kinetics and intrinsic dissolution of lithium polysulfides (LiPSs) critically hinder the desirable commercialization of Li-S batteries (LSBs). Purposeful modification of separators with multi-functional materials brings enormous room for both efficiently restraining the dissolution and enhancing the solid-liquid-solid conversion kinetics of LiPSs. For this, herein, hetero-architectured CoO-Co₃O₄ hollow nanotubes (HNTs) are elaborately designed and fabricated via a self-sacrifice template methodology to modify the polypropylene (PP) separator for advanced LSBs. Besides the robust physico chemical adsorption, the endogenous CoO-Co₃O₄ heterojunction, as authenticated by theoretical calculations and experimental verification, spontaneously creates an interfacial built-in electric field, which simultaneously enhances the active sites, accelerates the bi-directional sulfur conversion, and favors the fast electron/ion transport. Thanks to successful realization of the synergistic “electrostatic capture-energy barrier regulation-directional conversion” effect, LSBs with the hetero CoO-Co₃O₄ HNTs modified PP separator exhibit significantly improved electrochemical performance with the long-duration cycling stability for 1000 cycles at 5 C, and a large capacity of 631.5 mAh g⁻¹ even at a high sulfur loading (5 mg cm^‒2) and low electrolyte/sulfur ratio (8.0 µL mg⁻¹). More essentially, our contribution here offers a viable avenue for up-and-coming hetero-catalyst functionalized separator platforms toward next-generation LSBs and beyond.