A Heterogeneous Host Intercalation-Customized Efficient Dual Electrode–Electrolyte Interphase for Self-Enhanced Aqueous Zinc Metal Batteries

The practical operation of aqueous zinc-ion batteries is greatly influenced by the microenvironment of the electrode-electrolyte interface, while the structural instability and sluggish interfacial reaction kinetics at both cathode and anode sides are still critical challenges. This work develops a heterocation intercalation approach to unlock a robust La³⁺/Ca²⁺-Na_0.7MnO_2.05 (LCNMO) cathode material, which enables simultaneously constructing an efficient cathode-electrolyte interphase (CEI) and a compressed double electric layer (EDL) interphase during the first few charging cycles. These in situ-formed interphases can simultaneously alleviate the interrelated adverse issues including cathode dissolution, uneven deposition, severe side reactions, and sluggish reaction kinetics. Benefiting from that, the constructed aqueous Zn||LCNMO system was demonstrated to exhibit self-enhanced electrochemical performance. Impressively, it can display a 6000-cycle lifespan with a 73.7% capacity retention even at a high current density of 10 A g^-1. Besides, the corresponding pouch cell with a 10 mg cm^-2 loading enables providing a high reversible capacity of 14.8 mAh at 1 A g^-1 after 100 cycles. Such a heterogeneous intercalation paradigm creates a tandem effect to expand the regulatory area of guest cations, deepen the understanding of host intercalation chemistry, and boost the development of high-performance aqueous zinc-ion batteries.