Poly (ether ether ketone) (PEEK) porous membranes with super high thermal stability and high rate capability for lithium-ion batteries

Abstract Lithium-ion batteries are receiving intensive interest due to their promising prospect for electric vehicles. However, the safety issues and low rate capability of lithium-ion batteries limited their further development due to the poor dimensional thermo-stability and low electrolyte wettability of commercial polyolefin separators. Herein, we report a sponge-like porous poly (ether-ether-ketone) (PEEK) membrane with super high thermal stability and good rate capability for lithium ion batteries. The porous PEEK membrane showed no fusion deformation even at temperature of 350 °C, showing excellent thermal stability. An electrolyte uptake of 251% was obtained for a porous PEEK membrane, which was more than twice than that of a commercial PE separator, showing very good electrolyte wettability. As a result, the lithium-ion battery with a porous PEEK membrane showed a discharge capacity of 124.1 mA h g−1 at 5 C, showing good rate performance. The battery performance of a PEEK membrane after treating at 350 °C changed rarely. The PEEK membranes provide more options for cost-effective high power battery separators.