Fabrication of NiMn2O4 nanospheres and its hybrid with polyaniline for high energy and high power supercapacitor with long cycle stability

Abstract

NiMn2O4 nanospheres have been prepared by a solution combustion method and hybridised with polyanilne by the dilute polymerization method. The metal oxide and its polymer hybrid forms were characterized by several physicochemical methods and microscopic techniques. The capacitive nature and cyclic stability were studied by cyclic voltammetry and galvanostatic charge–discharge measurements. The newly fabricated NiMn2O4 nanospheres and PANI-NiMn2O4 nanohybrid showed high specific capacitance values of 374 Fg−1 and 442 Fg−1 respectively, at the scan rate of 10 mVs−1. The NiMn2O4 nanospheres showed enhanced energy density (13.8 WhKg−1) compared to its hybrid form (2.82 WhKg−1). However, the power density of the PANI-NiMn2O4 nanohybrid (565.2 Wkg−1) was found to be higher than that of the pure NiMn2O4 nanospheres (447.18 WKg−1). In addition to that, both the electrode materials showed the same columbic efficiency (∼96 %) after 1000 consecutive cycles.