The Chueh Group explores efficient electrochemical routes for converting solar energy to chemical fuels and subsequently to electricity. The group also develops next-generation electrochemical energy storage materials. We take a rational approach towards materials discovery and optimization. Using powerful electron, X-ray and optical microscopy and spectroscopy techniques, we visualize electrochemical reactions as they take place on length scales ranging from tens of microns down to sub-nm. These fundamental observations, combined with atomistic- and continuum-level models, lead to new insights into the design of functional materials with novel compositions and structures. We utilize a wide range of solution, vapor and solid-state routes to create high-performance electrochemical devices, such as photo-electrochemical cells, fuel cells, electrolyzers and metal-air batteries.