Waste heat is everywhere: car engines, industrial machinery, kitchen appliances—even your own body. Some of that lost energy can be converted into electricity using thermoelectric generators: compact, solid-state devices that produce power directly from temperature differences without the need for spinning turbines or moving parts. But designing materials that make these systems efficient has long been an engineering slog, requiring slow simulations and painstaking experiments to identify combinations that conduct electricity while limiting unwanted heat flow. Now researchers in Japan have built an artificial-intelligence tool that can design thermoelectric generators 10,000 times faster than conventional approaches.

Prototypes built based on the tool’s recommendations performed on par with today’s leading thermoelectric devices, the study found. The research, reported 15 April in Nature, could boost a long-promised but not widely adopted clean-energy technology by dramatically accelerating the search for affordable materials and device designs that efficiently convert heat into electricity. Takao Mori, deputy director of the Research Center for Materials Nanoarchitectonics in…