Iron molybdate and manganese dioxide microrods as a hybrid structure for high-performance supercapacitor applications

FeMoO4@MnO2 microrod binary hybrid structure is synthesized by a simple two-step hydrothermal method. The phase formation and morphology of FeMoO4@MnO2 were analyzed using X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) respectively. High-resolution transmission electron microscopy (HRTEM) analysis of the sample confirms its microrod morphology and polycrystalline nature. The electrochemical measurements revealed the supercapacitive behavior by encompassing both double layered capacitance as well as pseudocapacitance at lower and higher scan rates respectively. A symmetric fabrication method was employed using FeMoO4@MnO2 as both negative and positive electrode for electrochemical analysis. The symmetric supercapacitor cell yields a specific capacitance of 839.29 F g(-1) at a current density of 1 A g(-1) in addition to higher cyclic stability and performance. The sandwiched symmetric supercapacitor device displays a high specific energy density of 56.95 W h kg(-1) at a power density of 418.46 W kg(-1). In addition to that, the device showed a promising capacity retention of 87% with an efficiency 80% of after 10,000 cycles. The electrochemical results show that FeMoO4@MnO2 could present itself as a promising electrode material for the next generation supercapacitors applications.