High-Dielectric Ultrathin BaTiO₃ Anode via Electrophoretic Deposition: A Platform for Pseudocapacitive Li Storage and Interface Stabilization

We report the development of an ultrathin barium titanate (BaTiO 3, BTO) anode fabricated via alternating current electrophoretic deposition (AC-EPD), enabling an interface-sensitive platform for Li-ion batteries (LIBs). The additive-free design without conductive agents or binders allows direct probing of the intrinsic electrochemical behavior of BTO. Owing to its high dielectric constant, BTO generates a uniform internal electric field at the electrode–electrolyte interface, effectively suppressing localized field fluctuations and minimizing parasitic side reactions. This interface-stabilizing effect is especially advantageous for lithium metal systems, where controlling interfacial reactivity is critical for long-term performance. Beyond its role as a stable interfacial layer, BTO exhibits significant pseudocapacitive charge storage with a b value of 0.83 and high Li ion diffusivity (1.3 × 10 –8 cm 2 s –1 ), indicating its dual function as a Li ion storage medium and a Li ion-permeable passivation layer. The ultrathin BTO anode demonstrates excellent high-rate capability at a current density of 1 A g –1 . These results establish BTO as a multifunctional material capable of enhancing both energy storage and interfacial stability in next-generation LIBs.