Binary composites of nickel-manganese phosphates for supercapattery devices

Abstract This study demonstrates a cost-effective, facile and green synthesis of nickel-manganese (Ni-Mn) based binary metallic phosphates through a one-step sono-chemical method followed by calcination at 400 °C. The composites are further modified by changing the aspect ratio of Mn in Ni and utilized for high performance energy storage applications. The structure morphology of synthesized nanomaterials is investigated by performing X-ray diffraction (XRD) analysis. Among all, the composite with a concentration of Ni0.75:Mn0.25(PO4)2 exhibit the outstanding electrochemical performance by indicating high specific capacity (Qs) of 788.4 Cg−1 in three-electrode assembly. At last, the supercapattery is fabricated comprising of active material Ni0.75Mn0.25(PO4)2 as positive and activated carbon as negative electrode, which reveal exceptional results with a high specific energy and specific power of 64.2 Whkg−1 and 11,896 Wkg−1, respectively. This supercapattery device demonstrates excellent cyclic stability of 119% after 2000 continues GCD cycles. Our investigation reveals that the facile synthesis of these nanomaterials along with excellent electrochemical performance makes them valuable for the development of advanced high-performance energy storage devices.