Double Eutectic Electrolytes With Optimized Inner-Outer Solvation Shell Engineering for Interphase-Stabilized...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Eutectic electrolytes (EEs) show promise for zinc-metal batteries but face challenges with high viscosity and ion migration hysteresis.
• Hydration improves ion transport in EEs but exacerbates corrosion issues, limiting battery lifespan.

Purpose of the Study:

• To develop an advanced electrolyte system that overcomes the limitations of traditional EEs for improved zinc-metal battery performance.
• To achieve a balance between efficient ion transport kinetics and mitigation of corrosion-related degradation.

Main Methods:

• A novel double eutectic electrolyte (DEE) was designed utilizing strong Lewis acid-base interactions and a reconstructed hydrogen-bonding network.
• The DEE was investigated for its ability to modulate the electrochemical interface and form a stable solid electrolyte interphase (SEI) layer.
• Electrochemical performance was evaluated using symmetric cells, full cells, and pouch cells under various conditions, including low temperatures.

Main Results:

• The DEE system demonstrated significantly extended cycle lives in symmetric cells (5900 h at 1 mA cm⁻², 1 mAh cm⁻²; 3300 h at 4 mA cm⁻², 4 mAh cm⁻²).
• Exceptional low-temperature performance was observed, with sustained cycling for 8000 h at -20 °C (0.5 mA cm⁻²).
• Full cells achieved 1000 cycles with 82.4% capacity retention (N/P ratio 5.89), and pouch cells showed durability over 2000 cycles (0.5 A g⁻¹).

Conclusions:

• The developed DEE effectively balances ion transport and corrosion resistance, leading to enhanced zinc-metal battery stability and longevity.
• The DEE promotes the formation of a stable SEI layer, mitigating water corrosion and enabling uniform zinc deposition.
• This electrolyte system offers a promising solution for high-performance, durable zinc-metal batteries, including applications at sub-zero temperatures.