High-Entropy Deep Eutectic Solvent Achieves Ultra-Low Polarization Zinc Anode Chemistry

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Deep eutectic solvents (DESs) are green solvents with excellent electrochemical stability, making them suitable for battery electrolytes.
• However, high viscosity and low ionic conductivity in DESs cause significant cell polarization, limiting their practical use.
• Addressing this limitation is crucial for advancing DES applications in energy storage.

Purpose of the Study:

• To reduce cell polarization in deep eutectic solvents (DESs) for improved battery performance.
• To enhance the electrochemical properties of DESs by increasing their configurational entropy.
• To explore the potential of high-entropy deep eutectic solvents (HEDES) in zinc-based energy storage devices.

Main Methods:

• Engineered solvation structures to increase the entropy of DES, creating high-entropy deep eutectic solvents (HEDES).
• Investigated the theoretical impact of high entropy on aggregate formation and mass transfer kinetics.
• Tested the electrochemical performance of HEDES in zinc plating/stripping and zinc-ion capacitors.

Main Results:

• Successfully reduced cell polarization in DES to levels comparable to aqueous electrolytes.
• Achieved durable zinc plating/stripping behavior for over 2000 hours with low polarization using HEDES.
• Demonstrated stable performance of HEDES even in extreme environments and high discharge currents in zinc-ion capacitors.

Conclusions:

• Increasing the entropy of DES via disorder-making strategies effectively mitigates cell polarization.
• HEDES offers a promising pathway for developing advanced electrolytes for high-performance and stable zinc-based energy storage.
• This work provides valuable insights for designing next-generation electrolytes for batteries and capacitors.