Metal oxides are suggested as promising electrode materials for lithium-ion batteries (LIBs) and supercapacitors. We have employed hydrothermal/solvothermal methods to synthesize a wide range of new metal oxide based nanomaterials, and investigated their potential applications as electrode materials for LIBs and supercapacitors. In this talk, I will briefly discuss three types of metal oxides based on three different lithium storage mechanisms. (i) Specifically, we have synthesized hollow SnO₂ nanostructures by both templating and template-free methods, and further engineered them into SnO₂-carbon composite hollow structures to achieve significantly improved lithium storage properties. (ii) We also try to improve the lithium insertion properties of TiO₂polymorphs by engineering the crystal facets and nanostructures. (iii) We have also demonstrated the concept for conversion reaction compounds (e.g., Fe₂O₃) showing that the cycling performance can be improved by creating a porous/hollow structure. (iv) Lastly, I will talk about some of our most recent works about mixed metal oxide/sulide materials for LIBs and supercapacitors.