A ferroelectric (BaTiO₃) interlayer and field polarization treatment were introduced to set up a built-in field, which optimizes the transport mechanisms of Li⁺ in solid and liquid phases and thus enhances the rate performance and cycling stability of Si anodes. Also, a fast discharging and slow charging phenomenon was observed in a half-cell with a high reversible capacity of 1500.8 mAh g^-1 when controlling the polarization direction of the interlayer, which means a fast charging and slow discharging property in a full battery and thus is valuable for potential applications in commercial batteries. Simulation results demonstrated that the built-in field plays a key role in regulating the Li⁺ concentration distribution in the electrolyte and the Li⁺ diffusion behavior inside particles, leading to more uniform Li⁺ diffusion from local high-concentration sites to surrounding regions.

Directional Polarization of a Ferroelectric Intermediate Layer Inspires a Built-In Field in Si Anodes to Regulate Li⁺ Transport Behaviors in Particles and Electrolyte. Advanced Science 2024, 2402915.