Polymer, an alloy of PEI and PBPDA, has 4X energy density of standard capacitors while remaining stable at temperatures up to 482°F

https://www.eurekalert.org/news-releases/1116897

"polymer capacitors often brittle/ unusable under heat if without heavy/ expensive cooling... overcome using alloy having dielectric constant of 13.5 (value of 4 for each polymer alone), maintaining that value from -148 to 482°F... like oil/ water, the polymers don't mix, which promotes self-assembly into 3D structure that creates barriers against electric charge leaks... scalable since components cheap/ assembly simple... EVs' power electronics, aerospace, data centers, manufacturing"