Conducting polymer and carbon-based materials are important in supercapacitor applications as capacitive materials. However, the use of these materials alone limits their application due to poor rate capability and short lifetime or low capacitance. Herein, the supercapacitor electrodes were successfully synthesized by two step process on the carbon-felt. Firstly, S-GO, N-GO and Cl-GO was obtained by chronoamperometry method at room temperature. After, PANI composites were synthesized through a hydrothermal method with S, N and Cl heteroatom doped graphene oxide powders. The best specific capacitance for Cl-GO doped PANI (PANI/Cl-GO) electrode reaches 1217 mFcm ⁻² (608.3 Fg ⁻¹ ) at 4 A g ⁻¹ and, significantly higher that the results of PANI and other hybrids. Moreover, the symmetric supercapacitor using PANI/Cl-GO electrodes demonstrates excellent long-life performance after 5000 cycle (96.9%). The device has a maximum energy density of 42.8 Wh kg ⁻¹ while delivering a power density of 250 W kg ⁻¹ .

In this work, nitrogen doped graphene oxide powder (N-GrOP) was used as an additive for fumed silica based gelled electrolyte of valve regulated lead acid (VRLA) batteries for the first time in the literature. Optimum amount of additive was determined as 0.4 wt% N-GrOP by using of electrochemical methods and corrosion tests. The structural features of fumed silica based gelled electrolyte with and without N-GrOP was investigated by SEM analysis. Then, the effects of agitation time and stirring rate on the formation and structure of the fumed silica based gelled electrolyte were optimized as 180 min and 1250 rpm, respectively, by using of electrochemical technics. Corrosion tendency of the electrodes were determined by Tafel curves. Cyclic charge/discharge tests were also carried out to determine the discharge capacity of the electrolytes. The discharge capacities of fumed silica based gelled electrolyte with and without N-GrOP and non-gelled electrolyte were determined as 33 mAh·cm ⁻² , 16 mAh·cm ⁻² and 0.70 mAh·cm ⁻² at 20 mA·cm ⁻² charge/discharge current densities, respectively. The interaction of N-GrOP with hydrolyzed fumed silica particles occurred and the discharge capacities of the fumed silica-based gel electrolyte increased in VRLA batteries.

In this study, nitrogen doped graphene oxide(N-GO) and sulfur doped graphene oxide(S-GO) were produced in one step, and two of these prepared materials were converted into composite form with polyaniline(PANI). For the first time in the literature, triple composite electrode materials with two heteroatom doped graphene oxides and PANI were prepared for supercapacitors. In this context, heteroatom doped graphene oxides and PANI were characterized using spectroscopic and microscopic methods. With the ternary composites formed, anode and cathode electrode materials for coin cell type supercapacitors in asymmetrical form were characterized by electrochemical methods. The capacitive behavior of the prepared supercapacitors was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) method. The change of capacitive behavior according to the number of cycles was determined by cyclic charge-discharge tests. With the electrode materials obtained with heteroatom doped graphene oxides/PANI composites, it reached the highest areal capacitance value of 79.7 mF.cm⁻² at 10 mV.s⁻¹ scan rate. The coin cell type asymmetric supercapacitors retained more than 100% of their initial specific capacitance at the end of the 1500 cycle.