Regulating Electrolyte Microstructure via Anion-Solvent Coordination Enables Fast Interfacial Kinetics Toward...

Solvation structure regulation plays crucial roles in stabilizing the Zn anode by suppressing dendrite and hydrogen evolution, but sluggish ion transport results in poor rate performance of the anode. In this study, we proposed an "anion regulation" strategy by introducing amphiphilic benzyl alcohol (BA) to the Zn(OTf)₂ electrolyte, which modulated the electrolyte microstructure and dual solvation structure. BA provided weak solvation ability with Zn²⁺ and induced the Zn²⁺-OTf-BA dual solvation structure by anion-solvent interaction, which downsized the solvation clusters with improved microscopic uniformity, improving the Zn²⁺ diffusion kinetics. Synergistic regulation on the first solvation shell was also achieved, where BA not only reduced the coordinated water but also weakened the Zn²⁺-OTf^- interaction, accelerating the desolvation kinetics. Additionally, an inorganic-rich solid electrolyte interphase was constructed by anion decomposition, favorable for interfacial stability. Consequently, the modulated electrolyte enabled the Zn anode with impressive rate performance (1500 h, 10 mA cm^-2/10 mAh cm^-2; 294 h, 20 mA cm^-2/20 mAh cm^-2) and superior stability at 85% utilization (260 h). The 1.2 Ah Zn-NH₄V₄O₁₀ pouch cell also maintained cyclability (∼85.3% retention) over 200 cycles. This work provides a novel way of regulating the electrolyte microstructure to improve interfacial kinetics toward practical zinc-ion batteries.