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Summary In this work, sulfur‐doped graphene‐coated electrodes are prepared by cyclic voltammetry in different potential ranges and different cycles (from 10 to 50) for selective modification of electrodes by different functional groups. The prepared electrodes are characterized by spectroscopic, microscopic and electrochemical methods. In scanning electron microscopic analysis, formation of graphene layers and their porous structure have been determined. Electrochemical impedance spectroscopic and cyclic voltammetric analyses are also used in electrochemical characterization of the electrodes. Then, the prepared sulfur‐doped graphene‐coated electrodes by using cyclic voltammetry in one‐step and low cost are used as electrode materials of supercapacitor for the first time in the literature. Since the mesoporous structure of the electrodes prepared in lower potential ranges increases, specific capacitance of the electrodes increases from 74 to 1833 mF cm−2 with 10 mA cm−2 current density. This result shows that specific capacitances of prepared electrodes are higher than those of the electrodes prepared with metal‐doped in the literature.

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In this work, symmetrical supercapacitors in the form of coin cell types were produced by using S-doped graphene powders. Sulfur doped graphene powders were prepared by cyclic voltammetry in different...

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.