Effect of physical interaction between polyaniline and metal phosphate nanocomposite as positive electrode for supercapattery

The growth of portable technologies and electrical automotive industry has led to the development of supercapattery, as one of the options in the electrochemical energy storage system. In this work, nanocomposite of polyaniline-metal phosphate (comprising nickel phosphate-silver phosphate (Ni-3(PO4)(2)-Ag3PO4) nanocomposite) was synthesized by two-step route; a combination of sonochemical-calcination method, followed by the physical blending method. Structural and morphology studies reveal that crystalline Ag3PO4 which were decorated on amorphous Ni-3(PO4)(2) were supported by semi-crystalline PANI nanofibers. The electrochemical performance studies show the resultant PANI-Ni-3(PO4)(2)-Ag3PO4 exhibited significantly improved rate capability from 32% (Ni-3(PO4)(2)) to 73% with a maximum specific capacity of 677 C/g. The origin of the outstanding performance shown by PANI-Ni-3(PO4)(2)-Ag3PO4 was due to the synergistic effect produced by the conductive platform provided by PANI, redox behavior of Ni-3(PO4)(2) and extended channels provided by Ag3PO4. In order to evaluate the real-time performance of PANI-Ni-3(PO4)(2)-Ag3PO4, supercapattery devices were fabricated in a configuration of PANI-Ni-3(PO4)(2)-Ag3PO4//activated carbon (AC), Ni-3(PO4)(2)-Ag3PO4//AC and Ni-3(PO4)(2)//AC. PANI-Ni-3(PO4)(2)-Ag3PO4//AC produced a superior performance by providing specific energy of 38.9 Wh/kg at 400 W/kg compared to its counterpart devices. Moreover, the life cycle test of PANI-Ni-3(PO4)(2)-Ag3PO4//AC demonstrated high stability which lost only 12% of its initial capacity after 5000 cycles.