Study of capacitive properties in supercapacitor for copolymer of aniline with m-phenylenediamine

The copolymers were synthesized with different molar ratios of m-phenylenediamine to aniline (R for short) by a chemical oxidation method. The products were first used as electrochemical activity materials of the supercapacitor. Capacitive behaviors of the prepared copolymers in 1 mol center dot L-1 H2SO4 electrolyte were examined by electrochemical impedance spectroscopy, cyclic voltammeter, and galvanostatic charge/discharge. The relationship of molar ratios with capacitive property of the prepared products was investigated too. The results showed that the product with R of 2:98 displayed better electrochemical properties than that of the other products. Compared with the synthesized polymer in the absence of m-phenylenediamine, the polymerized copolymer with R of 2:98 exhibited the initial specific capacitance value of 475 F center dot g(-1), which increased by nearly 10.1% than that of the former at a current density of 200 mA center dot g(-1) in 1 mol center dot L-1 H2SO4 electrolyte in the potential range of -0.3 to 0.7 V. The discharge specific capacitance value of the copolymer remained 300 F center dot g(-1) after 1,000 cycles, exhibiting a good cycling performance and the structure stability.