High-Entropy Electrolytes Downsizing Solvated Clusters and Enabling Parallel Ion Transport for Low-Temperature...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Conventional aqueous electrolytes limit rechargeable zinc-based battery performance at low temperatures.
• Challenges include low deliverable capacity, poor rate capability, and reduced cycle life.

Purpose of the Study:

• To formulate a novel aqueous electrolyte for enhanced low-temperature performance of zinc-based batteries.
• To investigate the role of entropy in tuning electrolyte properties and zinc anode behavior.

Main Methods:

• Formulation of a ternary-chloride-salt high-entropy aqueous electrolyte.
• Characterization of electrolyte properties (freezing temperature, ionic conductivity, solvation structures).
• Electrochemical testing of Zn||Zn cells and full cells at low temperatures.

Main Results:

• The high-entropy electrolyte exhibited a lower freezing temperature and higher ionic conductivity.
• Entropy-mediated solvation structures facilitated uniform zinc plating/stripping with high Coulombic efficiency (99.97%).
• Stable cycling over 13320 hours was achieved at 1 mA cm⁻².

Conclusions:

• The developed electrolyte overcomes low-temperature limitations in zinc-based batteries.
• It enables efficient and stable zinc anode cycling via entropy-driven solvation.
• Full cells demonstrated reliable operation at -60 °C with various cathodes.