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

Abstract 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/Li 2 O) 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 LiFePO 4 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.