Research in the Choi Group employs electrochemistry as the primary synthetic tool to fabricate various solid-state materials as thin film-type electrodes and catalysts for electrochemical and photoelectrochemical applications critical to creating a sustainable future. These applications include (1) solar fuel production, (2) electrochemical biomass upgrading to fuels and chemicals, and (3) electrochemical water treatment and resource recovery. Recovery of Li from spent lithium-ion batteries and recovery of eutrophication-causing phosphate in wastewater as phosphoric acids for fertilizer production are examples of resource recovery. The goal is to enable sustainable and environmentally benign production of fuels, chemicals, and clean water using renewable energy sources (i.e., solar, biomass).