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

Résumé fourni par la source

Abstract 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/TiO 2 (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 mg s exhibits 9.3 mAh cm −2 under a lean electrolyte amount (5 µL mg −1 ), much better than state‐of‐art reports. As 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.

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