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Non-Cross-Linked Gel Polymer Electrolytes for Lithium Ion Batteries



  • Rechargeable lithium ion batteries for cellular phones, laptop computers and other consumer electronics
  • Batteries for electrically-powered vehicles
  • Electrical grid load leveling devices
  • Medical devices


  • High thermal stability
  • Low rate of self discharge
  • Safe, stable operation in a range of environmental conditions
  • Amenable to novel forms and packaging
  • Can be manufactured using conventional polymer processing methods



Nitash Balsara of Berkeley Lab and a team of scientists at Seeo, Inc. have jointly invented a class of nanostructured gel polymer electrolytes fro batteries that have both high ionic conductivity and high mechanical strength and that can be easily and affordably processed. The electrolytes consist of two domains formed by block copolymers. The first block provides a polymer matrix that can soak up a liquid electrolyte to make a gel. The other domain contains a rigid polymer that provides structure for the electrolyte and that swells less than 5% in the presence of the liquid electrolyte. The technology provides controlled, nanostructured pathways for ionic flow.

Gel Polymer electrolytes offer many advantages, such as safe and stable operation and an ability to be be used in different packaging formats, compared to traditional lithium-ion batteries using non-polymer liquid electrolytes. Until now, however, large quantities of plasticizers and/or solvents were added to the host polymer matrix of these electrolytes to achieve high conductivities. This led to deterioration of the mechanical properties neede to ensure that the electrolyte could be manufactured, stored and used. In addition, cross-linking or thermosetting the polymer matrix to achieve mechanical robustness added processing costs, reduced ionic activity and rendered most batteries non-recyclable.

The Berkeley Lab gel polymer electrolytes are not cross-linked and, therefore, offer all the advantages of the gel polymer electrolytes while maintaining high ionic conductivity and high mechanical strength and stability. In addition, the technology offers low reactivity with lithium and reduced volatility or vaporization of solvents.



  • Published PCT Patent Application WO2009/092058 available at Available for licensing or collaborative research.

DEVELOPMENT STAGE: Proof of principle.

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