Edge‐Delocalized Electron Effect on Self‐Expediating Desolvation Kinetics for Low‐Temperature Li─S Batteries

Lithium-sulfur (Li─S) batteries suffer from significant capacity degradation, which is limited by high barriers from interfacial desolvation, Li+ transportation to sulfur redox conversions, exhibiting the depressive kinetics. Herein, the electron effect in the edge of catalysts is modulated and the corresponding strategy of self-transform Schottky heterojunction on MXene is proposed to achieve the edge delocalized electronic density. As a protocol, the electron-delocalized Schottky heterojunction of boron-doped MXene/TiO2 (SH-MTB) is fabricated as electrochemical kinetic accelerators to realize fast Li+ desolvation to promote rapid sulfur conversion kinetics under low-temperature. Specifically, the Schottky heterojunction with edge effect expedites the dissociation kinetics of [Li(solvents)x]+ to generate free Li ions, as well-confirmed by theoretical calculations and ex-situ/in situ electrochemical characterizations. Encouragingly, higher practical areal capacity (5.0 mAh cm−2) and negligible self-discharge behaviors are achieved under low-temperature environments. A large areal pouch cell with 200 mgs exhibits 9.3 mAh cm−2 under a lean electrolyte amount (5 µL mg−1), much better than state-of-art reports. ... mehrAs further indicated by electronic microscopies, spectroscopical measurements and X-ray tests, the SH-MTB stabilizes the chemical structure during charge/discharge process, showing promising potential of Schottky heterostructure toward accelerating the cascade carrier kinetics in Li metal battery under low-temperature.