Optimization of LiCl concentration on polyaniline composites for symmetric and asymmetric supercapacitor devices

Abstract

Polyaniline doped lithium chloride (PANI-LC (1–7)) composites are synthesized via the in-situ chemical oxidative method by varying the Lithium Chloride (LC) concentrations from 0.0625 to 3 M for symmetric and asymmetric supercapacitor applications. The resultant composites are characterized through Thermogravimetric analysis and X-ray photoelectron spectroscopy. In addition they were subjected to electrochemical measurements such as cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy measurements. Because of its high specific capacitance and excellent capacitance retention, PANI-LC 6 composite is used to fabricate symmetric and asymmetric supercapacitors. The highest specific capacitance of 388 Fg−1 at a scan rate of 1 mV s−1 and 375 Fg−1 at a current density of 1 Ag−1 in 1 M H2SO4 is obtained for PANI-LC 6 composite. Maximum specific capacitance of 89 Fg–1 (symmetric device) and 60 Fg–1 (asymmetric device) is achieved at a current density of 2 Ag–1. Symmetric and asymmetric devices deliver the maximum energy density of 12.3 Whkg−1 and 16.4 Whkg−1 at a power density of 289 W kg−1 and 71.8 W kg−1, respectively.