Key Points * Solid-state batteries have long been billed as the “holy grail” of sustainable driving. Proponents say they offer safer, cheaper and more powerful batteries for electric vehicles (EVs), as well as faster charging times. * There could be another option, however: semi-solid-state batteries, which use a hybrid design of solid electrolyte and liquid electrolyte. * “Five years ago, if we talked about this, I would have been so excited about solid-state batteries,” Transport & Environment’s Julia Poliscanova said. “But somehow ... there is some kind of barrier today.” ============================================================================================= PARIS, France — The push to commercialize solid-state batteries...