As employee number seven at Tesla, Gene ­Berdichevsky was instrumental in solving one of its earliest challenges: the thousands of lithium-­ion batteries the company planned to pack into its electric sports car caught fire far more often than manufacturers claimed. His solution: a combination of heat transfer materials, cooling channels, and battery arrangements that ensured any fire would be self-contained.

Now Berdichevsky has cofounded Sila Nanotechnologies, which aims to make better lithium-ion batteries. The company has developed silicon-based nanoparticles that can form a high-capacity anode. Silicon has almost 10 times the theoretical capacity of the material most often used in lithium-ion batteries, but it tends to swell during charging, causing damage. Sila’s particles are robust yet porous enough to accommodate that swelling, promising longer-lasting batteries.

—James Temple