Polyaniline coated sugar derived soft carbon sphere as electrode material in all-solid state symmetric supercapacitor with enhanced cyclic stability

Abstract

Design and bulk synthesis of low cost electrode materials with high energy density and improved cyclic stability is extremely important. We have synthesized sugar derived soft carbon spheres by simple one step hydrothermal method. To increase the energy density, we coated the carbon spheres with polyaniline via vapour phase and colloidal chemical polymerization methods. By colloidal synthesis method, two composites CS-PANI-11 and CS-PANI-31 were prepared by using CS: aniline (w/w) ratios 1:1 and 3:1 respectively whereas the sample prepared by vapor phase polymerization is denoted as CS-PANI-VP. The performance of these four electrode materials depending on specific capacitance and specific energy is in the order CS< CS-PANI-VP< CS-PANI-31 < CS-PANI-11. The best performing material CS-PANI-11 showed specific capacitance, specific energy and specific power of 84.3 F g−1, 11.7 W h kg−1 and 500 W kg−1 respectively at current density 1 A g−1. Moreover the symmetric cell constructed by using CS-PANI-11 as electrode material gave areal capacitance, energy density and power density values 42 mF cm−2, 5.8 μW h cm−2 and 50 μW cm−2 respectively at current density 0.1 mA cm−2. This symmetric SC showed capacitance retention of 80.33 % after 5000 galvanostatic charge discharge cycles demonstrating excellent cyclic stability.