Scalable Manufacturing of Solid Polymer Electrolytes with Superior Room-Temperature Ionic Conductivity

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Developing flexible, solvent-free solid polymer electrolytes (SPEs) is crucial for next-generation energy storage.
• Existing SPEs often face challenges with ionic conductivity and mechanical stability, limiting their practical application.

Purpose of the Study:

• To develop a scalable manufacturing protocol for solvent-free, all-solid flexible energy storage devices.
• To investigate the properties of polymer-based SPEs for enhanced ionic conductivity and thermal stability.
• To fabricate and evaluate flexible supercapacitors utilizing the developed SPEs.

Main Methods:

• Utilized a two-roll mill and adapted rubber mixing technology for scalable SPE preparation.
• Characterized SPEs using ionic conductivity measurements, small-angle X-ray scattering (SAXS), infrared spectroscopy (IR), and rheology.
• Assembled flexible supercapacitors with carbon black-filled electrodes and evaluated their performance, including voltage window, energy density, and temperature tolerance.

Main Results:

• Achieved superior ionic conductivity of 2.7 × 10⁻³ S cm⁻¹ at 30 °C in SPEs composed of poly(methyl methacrylate)-grafted natural rubber (MG) and lithium bis(trifluoromethanesulfonyl)imide.
• Confirmed the formation of an ionic cluster network in the SPEs via SAXS and IR.
• Demonstrated good mechanical stability with a storage modulus > 1 × 10⁴ Pa from 30 to 120 °C.
• Fabricated flexible supercapacitors exhibiting a 3.5 V voltage window, 28.4 μW h·cm⁻² energy density at 160 °C, and excellent temperature tolerance up to 160 °C.

Conclusions:

• The developed scalable manufacturing strategy for SPEs shows significant potential for advancing flexible energy storage devices.
• The high ionic conductivity and robust mechanical/thermal properties of the SPEs are attributed to the ionic cluster network.
• The successful fabrication of high-performance flexible supercapacitors highlights the practical viability of this approach.