Wide‑temperature electrolytes for aqueous alkali metal‑ion batteries: Challenges, progress, and prospects

As global energy storage demands diversify, the limitations of conventional aqueous batteries in extreme temperatures become more pronounced. Now, researchers from Wuhan University of Science and Technology, the University of Adelaide, and the National University of Singapore, led by Professor Kaifu Huo, Professor Yang Zheng, and Professor Yu Liu, have published a comprehensive review on wide-temperature electrolytes for aqueous alkali metal-ion batteries (AAMIBs). This work offers valuable insights into the design of next-generation energy storage systems that can operate reliably across broad temperature ranges.

Why Wide-Temperature Electrolytes Matter

• Safety & Stability: Aqueous electrolytes are non-flammable and environmentally friendly, but their performance drops sharply at low and high temperatures.
• Grid-Scale Potential: AAMIBs are promising for large-scale energy storage due to the abundance of Na and K, but temperature sensitivity limits their deployment.
• All-Climate Operation: Wide-temperature electrolytes enable batteries to function in extreme environments, from polar regions to desert climates.

Innovative Design and Features

• Hydrogen Bond Engineering: The review highlights how disrupting water’s hydrogen bond network can lower freezing points and suppress water activity at high temperatures.
• Multi-Strategy Approaches: Key strategies include high-concentration salts (WISE), organic co-solvents, hydrogels, and additives like HBCD and GOQDs to tune electrolyte structure and stability.
• Fundamental Insights: Thermodynamic and kinetic interpretations are provided to explain how ion–water interactions affect phase transition temperatures, ionic conductivity, and electrochemical stability.

Applications and Future Outlook

• Low-Temperature Performance: Electrolytes with freezing points below −100 °C and ionic conductivities above 1 mS cm^-1 at −50 °C have been demonstrated.
• High-Temperature Durability: Strategies like colloidal electrolytes and thermo-responsive hydrogels improve water retention and suppress side reactions up to 100 °C.
• Challenges & Opportunities: The review outlines future directions, including multi-salt systems, eco-friendly additives, and AI-assisted electrolyte design to balance cost, safety, and performance.

This comprehensive review provides a roadmap for developing wide-temperature electrolytes that can unlock the full potential of aqueous alkali metal-ion batteries. It emphasizes the importance of interdisciplinary research in chemistry, materials science, and engineering to drive innovation in sustainable energy storage. Stay tuned for more groundbreaking work from Professor Huo, Professor Zheng, and Professor Liu’s teams!