Prof. Fangyi Cheng's research interests focus on electrode materials for electrochemical energy conversion and storage. He proposed new mild strategies for selective preparation of a series of spinel and perovskite-type 3d metal oxides with tunable shape, size, oxygen deficiency and metal valence. He elucidated the effect of nonstoichiometry on enhancing the electrocatalytic oxygen reduction/evolution activity and ion-intercalation performance. By applying oxygen-vacant and cation-defective spinel oxide as bifunctional oxygen catalyst and Zn-insertion cathode material respectively, he developed rechargeable zinc-air batteries and aqueous zinc batteries featuring high-rate capability and long cycle life.