Ferroelectric-Field-Steered SEI Engineering for Long-Life Lithium-Metal Batteries

The design and controllable regulation of the solid-electrolyte interphase (SEI) remain pivotal yet elusive for high-performance lithium-metal batteries. Conventional strategies, dictated by thermodynamic nucleation sequences have limited ability to steer interfacial reactions. Here we introduce the electric-field vector as a geometric order parameter to actively reconfigure the interfacial double layer and in turn, the SEI chemistry. A ferroelectric metal-organic-framework (MOF) interlayer establishes a built-in reverse electric field that enriches anions at the Li surface, triggering their preferential reduction and constructing an inorganic-dominant (LiF/Li₂O) SEI that effectively suppresses dendrite growth. Consequently, Li||Li symmetric cells cycle stably for 2000 h at 0.5 mA cm^-2 with < 20 mV polarization, and LiFePO₄ full cells maintain >95% capacity after 1000 cycles at 2 C/5 C. This field-oriented strategy transcends traditional material screening, opening an additional dimension for electric-field-driven interface engineering toward safe and durable high-energy batteries.