In an entirely new approach to making lithium-ion batteries lighter, safer and more efficient, scientists at Stanford University and the Department of Energy's SLAC National Accelerator Laboratory have reengineered one of the heaviest battery components—sheets of copper or aluminum foil known as current collectors—so they weigh 80% less and immediately quench any fires that flare up.
source https://techxplore.com/news/2020-10-approach-boosts-lithium-ion-battery-efficiency.html