2014 SYMMETRIX® HPX-F lithium-ion battery nanocomposite separator Southeast

Porous Power Technologies, LLC (PPT), in collaboration with Oak Ridge National Laboratory (ORNL), has developed SYMMETRIX® HPX-F, a polymer-ceramic composite separator for commercial lithium-ion batteries that is much safer than conventional polyethylene and polypropylene-based membranes. It uses three material constituents to form a novel microstructure: a nonwoven polymer-fiber backbone, a nanodispersed ceramic filler, and a polymer binder.

A Cooperative Research and Development Agreement (CRADA) between ORNL and PPT, executed in 2010 and concluded in 2012, led to the successful commercialization of SYMMETRIX® HPX-F. ORNL's primary role during product development was to provide insight to the physical and chemical properties of the separator, as well as information about its microstructure. The ORNL staff's expertise was key in suggesting additional testing methods and novel approaches to technical investigation. ORNL also provided expertise on lithium-ion cell and process development to correlate the nature of the composite separators with cell performance data and key processing parameters. PPT fed this information into the development of novel separator microstructures and the associated new manufacturing methods required to produce high volumes of HPX-F. With the technical information and guidance provided by ORNL, PPT was able to down-select a variety of raw materials to a final commercial HPX-F formulation that can be manufactured cost-effectively. This fruitful partnership significantly accelerated the commercialization of HPX-F, and is a shining example of how national laboratory resources should be used to enhance product development and industrial innovation.

SYMMETRIX® HPX-F shows excellent retention of mechanical strength when subjected to compression fatigue, improved resistance to internal short-circuiting when exposed to external force, increased time to thermal runaway during accelerated rate calorimetry, and a microstructure that improves long-term cell cycling performance by 7% to 8%. As a result of this collaborative effort, the SYMMETRIX® HPX-F technology is leading the way in the quest for lithium-ion battery separators that drastically improve the safety of high-energy cells for transportation, grid storage, and portable electronics applications.

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