Solid electrolyte and method for manufacturing the same

Eco-friendly solid electrolyte using ammonium-bonded cellulose nanofibers and hydroxide ion exchange

This technology is a method for manufacturing a cellulose-based solid electrolyte that achieves both high ionic conductivity and mechanical properties by bonding ammonium ions to cellulose nanofibers via halogen ion mediation, followed by exchanging residual halogen ions with hydroxide ions.

Conventional gel polymer electrolytes face a trade-off: increasing liquid content to improve ionic conductivity compromises mechanical strength, while increasing polymer content to reinforce strength reduces ionic conductivity.

This technology treats cellulose nanofibers in a solvent containing ammonium and chloride (Cl-) ions to stably bond ammonium ions to the fiber surface, and utilizes primary metal cations like K+ to enhance the efficiency of ion exchange with hydroxide (OH-) ions. It can be applied to electrolyte membranes for metal-air batteries, such as zinc-air batteries, and flexible wearable power sources, offering the advantage of designing flexible, leak-proof cells using biomass-derived materials.

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Key Features:

• Preparing a cellulose mixture solution by dispersing cellulose nanofibers in a solvent containing ammonium and halogen ions
• Obtaining ammonium-bonded cellulose nanofibers from the cellulose mixture solution to manufacture a cellulose membrane
• Manufacturing a solid electrolyte by exchanging residual halogen ions in the cellulose membrane with hydroxide (OH-) ions
• A metal-air battery featuring the cellulose solid electrolyte placed between an anode containing an aerogel composite and a spaced-apart cathode

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This invention was developed with support from the Ministry of Science and ICT for the development of high-power Pt-free photoelectrochemical-thermoelectric fusion devices using solar-waste heat energy.

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