Mixed transition metal oxides with adjustable composition and structures are widely used in electro chemical cell applications such as lithium-ion batteries and supercapacitors their high theoretical capacity, high energy density, high cyclic durability, and environment friendliness compared to mono metal oxides. Different routes like sol gel, combustion, solvothermal, sonication, hydrothermal are used for their synthesis. This chapter gives an overview of some of the key MTMOs in different structural and forms like layer, core-shall, nanorods, nanosheets etc and in the forms of composites with materials like PANI, rGO, CNT, CNF etc