Concentration-function coupled electrolytes harmonize thermodynamics and kinetics for stable zinc metal batteries

Abstract

The application of zinc-based aqueous batteries (ZABs) is limited by poor thermodynamic stability and sluggish electrochemical kinetics due to the unfavorable bulk phase and interface. Conventional electrolyte strategies struggle to balance these aspects. Here, we present a concentration-function coupled electrolyte strategy that enables the independent yet synergistic regulation of bulk and interfacial behaviors of Zn²⁺. Variations in molecular dipole moment, polarity, and concentration determine their coordination with Zn²⁺ and interfacial affinity, enabling the regulation of bulk and interfacial structures, thereby achieving a delicate trade-off between thermodynamics and kinetics. The high-concentration bulk-phase regulator reconstructs the hydrogen-bond network and Zn²⁺ coordination, effectively suppressing hydrogen evolution and zinc corrosion. Meanwhile, the low-concentration interfacial regulator modulates the electric double layer, promoting uniform Zn deposition via favorable interfacial chemistry. This electrolyte strategy achieves ultra-stable zinc anodes at room/low temperatures. The strategy's practicality is validated in Zn‖Zn_xV₂O₅·nH₂O full cells (95% capacity retention after 4600 cycles), establishing a new paradigm for electrolyte design and offering key insights into the development of durable high-performance ZABs.