Self-standing star-shaped tri-metallic oxides for pseudocapacitive energy storage electrode materials

Novel star-shaped trimetallic oxides (CuMnCoO4) have been synthesized employing hydrothermal method and favorably compared to the Co3O4 and bimetallic (MnCo2O4) oxides. The star-shaped CuMnCoO4 consisted of bundles of orderly layered and loosely interconnected nanoneedles with a hole in the center; each nanoneedle was composed of single-crystalline nanoparticles. Its distinctive structural features significantly increased the electrochemically active sites and facilitated the mass and charge transports. Furthermore, the three transition metal cations in the trimetallic oxide contributed to the multiple redox reactions. Consequently, CuMnCoO4 exhibited a significantly enhanced capacitance (1,715F g(-1) at 1 A g(-1)) and outstanding cycling stability, compared to those of Co3O4 (742F g(-1)) and MnCo2O4 (1,305F g(-1)). Additionally, an asymmetric supercapacitor (AS) (assembled with CuMnCoO4, as the positive electrode, and activated carbon (AC), as the negative electrode) exhibited a high energy density (E) of 40.1 W h kg(-1), at a power density (P) of 799 W kg(-1), thereby highlighting CuMnCoO4 as a promising candidate for energy storage. This research can also pave the way for the study of new spinel-trimetallic compounds with EES applications.