A High Performance Battery Separator

The broad adoption of lithium-ion batteries in electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles requires ultrahigh safety battery separators characterized by high temperature integration and long term stability. Commercial polymer based battery separators exhibit extensive thermal shrinkage and significant structural degradation when exposed to high- temperature environments, which may trigger internal short circuits in the lithium-ion batteries. Thus, the commercial polymer based battery separators cannot meet these high safety requirements, and a new generation of ultrahigh safety battery separator is needed to address this formidable challenge. Leveraging our technical leadership on the preparation and processing of ceramic nanowires at large scale and low cost, we propose to develop a new generation high safety battery separator by using ceramic nanowires. The proposed battery separator will provide high temperature stability, long term stability and high ion conductivity, which are unachievable by the state-of- the-art commercial separators. We will fabricate alumina nanowire battery separators and battery pouch cell prototypes by using them as the separators. At the end of the Phase I program, alumina nanowire separators and battery prototypes with the targeted excellent performance will be demonstrated. Lithium-ion batteries with higher safety and longer life are critical to the arrival of the electric vehicle era. It is predicted that the overall market for lithium-ion battery separators is going to grow to $2.5 billion in 2020, and majority is for electric vehicle use. In addition, grid storage and residential electricity storage will also need the proposed high safety battery separator technology. The successful commercialization of the proposed separator technology will assure the large scale commercial use of large format lithium-ion batteries in electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles.