Lithium-Mediated Ammonia Electrosynthesis over Orderly Arranged Dipoles Regulated Solid-Electrolyte Interphase

The electrocatalytic lithium-mediated nitrogen reduction reaction (Li-NRR) is considered as a promising alternative to the energy-intensive Haber-Bosch route. However, the solid electrolyte interphase that is derived from the electrolyte easily hinders the diffusion and nucleation of Li⁺, which ultimately suppresses N₂ activation and the subsequent protonation process. Herein, we successfully construct surface oxygen vacancies (O_v) on commercial BaTiO₃ (BTO) nanoparticles and further drive the phase transition from cubic/tetragonal to rhombohedral, which enhances the ferroelectricity of O_v-enriched BaTiO₃ (BTOV) and produces orderly arranged dipoles. Systematic experimental and computational results validate that O_v-induced orderly arranged dipoles readily bind anions in the electrolyte and promote their reduction to form a LiF-rich SEI. The optimized anion-derived SEI enhances the Li⁺ transfer kinetics and effectively facilitates the uniform nucleation of Li⁺, which enables lower energy of Li⁺ desolvation and the reactant crossing the SEI. Thus, the as-prepared BTOV delivers a faradaic efficiency of 93.01% and an NH₃ yield rate of 6.94 nmol s^-1 cm^-2 at -0.5 V which achieves more than a 45-fold performance improvement compared to the BTO counterpart. This work opens new horizons for the introduction of orderly arranged dipoles to modulate SEI chemistry and further enhance the intrinsic activity of the Li-NRR.