The lab at QuantumScape, a Silicon Valley start-up whose investors include Volkswagen and Bill Gates, is working on a technology that could make car batteries cheaper, more reliable and quicker to recharge. (Gabriela Hasbun/The New York Times)

QuantumScape is a Silicon Valley startup whose investors include Volkswagen and Bill Gates. Much of the excitement around QuantumScape stems from the company’s assertion that it has found a material that solves one of the main impediments to mass production of solid-state batteries, namely their tendency to short circuit if there are any imperfections.