Biomimetic Membrane-Like Co/CoSe2@CNF-CNT (L) with Selective Permeability for Enhanced Performance of Lithium-Sulfur Battery.

Abstract

Inspired by the multifunctionality and precise regulation of biological membranes, this work designs a biomimetic membrane-like structure for lithium-sulfur (Li-S) batteries. By controlling the selenization time, the composition of the metal catalyst and the material's microstructure is regulated, resulting in a self-supporting 3D porous conductive network of Co/CoSe₂-modified carbon nanofiber (CNF) with in situ grown carbon nanotubes (CNT) (Co/CoSe₂@CNF-CNT (L)). Drawing inspiration from the selective permeability of biological membranes, the Co/CoSe₂@CNF-CNT (L) system achieves dual-functionality. On one hand, the Co/CoSe₂ catalyst, possessing Lewis acid properties, provides a strong binding affinity for lithium polysulfides (LiPSs), effectively inhibiting their migration. Additionally, CNF and in situ grown CNT form a microporous structure, which effectively inhibits the shuttle effect. This behavior is analogous to specific proteins in biological membranes that selectively recognize and bind certain substances. On the other hand, the CNF-CNT 3D conductive network has numerous ion channels that ensure efficient lithium-ion (Li⁺) transport, mirroring the role of ion channels or carrier proteins in biological membranes. Consequently, the cell with the Co/CoSe₂@CNF-CNT (L) exhibits a reversible capacity of 1425.21 mAh g^-1 at 1 A g^-1 and retains 875.33 mAh g^-1 after 500 cycles. Furthermore, the cells exhibit excellent stability under high currents and prolonged cycling.