Nanoconfinement-cooperated catalysis enables rapid tandem redox kinetics for wide-temperature lithium-sulfur batteries

Abstract

The slow kinetics of sulfur cathodes caused by the high energy barriers of Li + desolvation stem primarily from the structure of the inner Helmholtz plane (IHP). Herein, a synergistic strategy combining electrochemical tandem catalysis with spatial nanoconfinement is proposed to regulate the Li(solvent) x + dynamics. As a proof-of-concept, the porous covalent organic framework (denoted as TPBD) decorated MXene is in situ constructed, acting as a tandem kinetic promoter. The theoretical simulations and in situ Raman reveal that the porous TPBD layer confines the bulky Li(solvent) x + species and sieves the spatial structure with accelerated Li + diffusion kinetics. Meanwhile, MXene serves as a negatively charged substrate that helps disrupt anion-solvent interactions and reconstruct the solvation structure at the IHP, thereby enhancing Li + kinetics and sulfur redox reversibility. Encouragingly, the assembled cells demonstrate a superior Li + transference number (0.77), long-term cycling lifespan up to 1000 cycles, as well as excellent areal capacity (>6 mAh cm −2 ) at 0°C and superior rate capability at 50°C under a high sulfur loading of 7.51 mg cm −2 . The as-prepared pouch cell remains stable for over 100 cycles, validating this novel integration of catalysis and nanoconfinement for tandem kinetics in Li-S batteries.