Ionic Liquid-Based Electrolyte with Multiple Hydrogen Bonding Network Enabling High-Voltage Stable Proton Batteries...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Proton batteries offer high safety and rapid response for energy storage.
• Acidic aqueous electrolytes limit proton battery energy density and stability due to a narrow electrochemical window.

Purpose of the Study:

• Develop a stable, high-voltage electrolyte for proton batteries.
• Enhance the energy density and operational stability of proton batteries.

Main Methods:

• An ionic liquid (IL)-based electrolyte (EMImOTf-H3PO4) was synthesized using 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMImOTf) and H3PO4.
• A hydrogen bonding network was formed within the electrolyte to prevent decomposition.
• Half-cell and full-cell configurations were tested using pre-protonated vanadium hexacyanoferrate (H-VHCF) and PTCDA/MXene electrodes.

Main Results:

• The EMImOTf-H3PO4 electrolyte demonstrated a 126% improvement in Coulombic efficiency compared to aqueous electrolytes.
• A full battery achieved an operating voltage of 2V at room temperature.
• The battery retained 86.1% capacity after 30,000 cycles and operated stably from -60°C to 50°C.

Conclusions:

• The developed IL-based electrolyte enables stable, high-voltage proton batteries.
• This technology presents new possibilities for all-weather grid-scale energy storage.
• The proton battery exhibits excellent energy density (87.5 Wh kg-1) and power density (30.6 kW kg-1).