Composite fiber, solid electrolyte containing the same, and metal-air battery containing the same

Bio-cellulose solid electrolyte cross-linked with TEMPO-oxidized fibers and quaternary nitrogen fibers

This technology is a solid electrolyte that enhances both ionic conductivity and mechanical stability by cross-linking TEMPO-oxidized fibers with nitrogen-functionalized fibers, utilizing a base fiber composed of bacterial cellulose (BC) combined with chitosan.

Conventional electrolytes for metal-air batteries suffer from low ionic conductivity, short lifespans, and dendrite growth. They are particularly limited by mechanical instability in flexible environments.

This technology consists of a network-structured membrane formed by mixing and cross-linking, at a 30–70 wt% ratio, fibers surface-oxidized with TEMPO to facilitate OH- ion transport and fibers functionalized with quaternary nitrogen groups to improve thermal stability and ion-exchange capacity. Applicable to zinc-air batteries, flexible power sources for wearables, and eco-friendly disposable sensor power, it reduces the risk of electrolyte membrane tearing or dendrite penetration even under repeated bending.

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Key Features:

• Base composite fibers containing both bacterial cellulose and chitosan bound to the bacterial cellulose
• First composite fibers, which are surface-oxidized base composite fibers included at a ratio of more than 30 wt% and less than 70 wt%
• Second composite fibers formed by bonding the surface of the base composite fibers with a first functional group containing nitrogen
• Solid electrolyte formed by cross-linking the first and second composite fibers

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This invention was developed with support from the Ministry of Science and ICT for the development of a high-energy-density soft materials platform through the design of new organic superionic plastic crystal materials.

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