Interface Passivation Inhibition Enabled by Anode–Cathode Synergistic Engineering for High-Efficiency Electrodeposition of Transition Metals

Room-temperature electrodeposition is widely used to fabricate transition-metal materials and alloys, but severe interfacial passivation drastically reduces current efficiency. More importantly, the intrinsic origin of interfacial passivation remains insufficiently understood, which has hampered the development of effective mitigation strategies. Herein, taking multivalent Ti as a representative example, we demonstrated that the bonding between Ti−Cl and the electrode downshifts the d-band center of the electrode by 0.15 eV, markedly suppressing ion adsorption and charge transfer at the interface. Further operando studies showed that anodic dissolution generated [Ti(Al₂Cl₇)₄]²⁻ with a unique coordination environment that prevented the bonding between Ti–Cl and the electrode, while offering a faster migration rate and lower desolvation energy. Building on these insights, anodic and cathodic potentials were co-regulated to couple Ti (II) dissolution and deposition. Furthermore, an optimized pulsed electrolysis protocol was introduced to jointly regulate interfacial ion migration and reaction kinetics, consequently maintaining stable electrode potentials for Ti/Ti (II) redox. Enabled by this anode–cathode synergistic engineering, an unprecedented current efficiency 93% was achieved even at a high Ti content. This work provides electronic-scale insight into the interfacial passivation during room-temperature transition-metal electrodeposition and offers a straightforward and implementable strategy for scalable manufacturing of transition-metal materials and alloys.