Metal oxides (MOs) have attracted extensive attention because they possess various applications such as lithium- ion batteries (LIBs), dye sensitized solar cells (DSSCs), fuel cells, catalysis, gas sensors, water splitting and supercapacitors due to low cost and high compatibility with the environment. This paper is a review on recent patents and scientific research literatures related to the synthesis, and energy storage and conversion of MOs in LIBs, DSSCs and supercapacitors. These MOs are mainly transition MOs such as Co3O4, CoO, Fe2O3, Fe3O4, Mn3O4 and MnO2. Some patents and scientific research literatures are also involved in MOs such as Cu2O, TiO2, NiO, SiO2, SnO, ZnO, SnO2, Zn2SnO4-SnO2 and ruthenium oxide. In addition, some problems existing with energy storage and conversion, and future research directions are also addressed.