Fluorine-Aligned Electrostatic Gatekeepers Regulating Polysulfide Migration for Stable Lithium–Sulfur Batteries

초록

The commercial viability of lithium–sulfur batteries is fundamentally limited by the shuttle effect, in which the uncontrolled migration of soluble lithium polysulfides triggers cascading active material loss and catastrophic anode degradation. While conventional separator engineering strategies predominantly rely on affinity-based adsorption, these approaches inevitably compromise Li+ transport and lead to irreversible sulfur loss. Herein, we report a paradigm-shifting polysulfide-repulsive interface, featuring highly oriented C─F dipoles anchored on an MXene scaffold. Unlike passive adsorption barriers, this electrostatic gatekeeper exploits the strong molecular polarization of β-phase poly(vinylidene fluoride) (β-PVdF) to create a persistent electrostatic field that actively repels anionic polysulfide species. This push-back mechanism effectively confines redox intermediates within the cathode region. Therefore, the electrostatically repulsive separator enables an exceptional cycling lifespan (804 mAh g−1 after 700 cycles at 0.5C). This work establishes a dipole-engineered transport regulation strategy that provides a robust blueprint for achieving long-term interfacial stability in high-energy-density storage systems.

키워드