Achieving Highly Stable Zn Metal Anodes at Low Temperature via Regulating Electrolyte Solvation Structure

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc metal is a promising anode for rechargeable aqueous zinc-ion batteries (ZIBs).
• Key challenges include dendrite formation, water-induced parasitic reactions, and poor low-temperature performance of aqueous electrolytes.
• These issues hinder the commercialization of ZIBs.

Purpose of the Study:

• To investigate tetrahydrofuran (THF) as an electrolyte additive for improving zinc anode reversibility and stability in ZIBs.
• To elucidate the mechanism by which THF mitigates water-induced side reactions and enhances low-temperature performance.
• To assess the long-term stability and electrochemical performance of THF-modified zinc anodes and full cells.

Main Methods:

• Theoretical calculations to understand solvation structure and interactions.
• Experimental electrochemical testing of zinc anodes and full cells.
• Analysis of electrolyte and electrode interface chemistry.

Main Results:

• THF addition optimizes solvation structure, reducing water-induced side reactions and protecting the zinc anode from corrosion.
• THF acts as a hydrogen bond acceptor, decreasing free water activity and improving low-temperature performance.
• Zinc anodes exhibited high cyclic stability (2800 h at 27°C, >4000 h at -10°C).
• Full cells demonstrated excellent cyclic stability and rate capability at both 27°C and -10°C.

Conclusions:

• THF is an effective additive for stabilizing zinc anodes in aqueous ZIBs.
• This approach enhances electrochemical performance across a range of temperatures, addressing critical commercialization barriers.
• The findings offer a new strategy for tailoring aqueous electrolyte and anode interface chemistry for advanced ZIBs.