Gopi Undavalli Venkata, S M Akash Sai, Smaran Kumar Sai
Department of Chemistry, Sri Sathya Sai Institute of Higher Learning (Deemed to be University), Prasanthi Nilayam Campus,, Prasanthi Nilayam, Andhra pradesh, 515134, INDIA.
Nanotechnology. 2025 Jun 23. doi: 10.1088/1361-6528/ade71f.
An adoption of a redox-active species can be instrumental in enhancing the specific capacitance of Electrical Double Layer Capacitors (EDLCs). Nitrogen-self-doped activated carbon (NDAC), derived from jack bean meal, exhibits a consistent distribution of nitrogen throughout a graphitized carbon framework, making it an ideal electrode for EDLCs. To enhance its capacitive properties, we integrated it with the redox additive para-phenylene diamine (PPD) and a gel polymer electrolyte made of poly (vinyl alcohol) and potassium hydroxide (PVA-KOH). Overlapping operative potential range of PPD with NDAC was the selection criterion. Further, the effects of concentration-dependent performance analysis interlinking PPD and PVA-KOH was evaluated via electrochemical studies. In a three-electrode setup, 25 mM PPD increased the specific capacitance six-fold to 835 F g⁻1 at 1 A g⁻1. Dunn's deconvolution analysis revealed a predominantly diffusive charge storage mechanism (75.8%), confirming the redox-active contributions. In a two-electrode symmetric supercapacitor (SSC), a blended gel polymer electrolyte of PVA-KOH and PPD delivered 179.94 F g⁻1 at a current density of 1 A g⁻1, demonstrating 77.5% capacitance retention and 99.4% coulombic efficiency after 10,000 cycles at 40 A g⁻1. Voltage-holding and self-discharge studies confirmed excellent stability, low leakage current, and minimal self-discharge. It was identified that 10 mg of PPD was an ideal concentration, enabling an energy density of 35.99 Wh kg⁻1 at a power density of 900 W kg⁻1. Thus, the results emphasized the synergy between PPD blended gel polymer electrolytes and NDAC as an ideal combination for high-performance supercapacitors.
采用氧化还原活性物质有助于提高双电层电容器（EDLC）的比电容。从刀豆粉衍生而来的氮自掺杂活性炭（NDAC）在石墨化碳骨架中呈现出均匀的氮分布，使其成为EDLC的理想电极。为了增强其电容性能，我们将其与氧化还原添加剂对苯二胺（PPD）以及由聚乙烯醇和氢氧化钾制成的凝胶聚合物电解质（PVA-KOH）相结合。PPD与NDAC的重叠工作电位范围是选择标准。此外，通过电化学研究评估了与PPD和PVA-KOH相关的浓度依赖性性能分析的影响。在三电极设置中，25 mM的PPD在1 A g⁻¹时将比电容提高了六倍，达到835 F g⁻¹。邓恩去卷积分析揭示了主要的扩散电荷存储机制（75.8%），证实了氧化还原活性的贡献。在两电极对称超级电容器（SSC）中，PVA-KOH和PPD的混合凝胶聚合物电解质在1 A g⁻¹的电流密度下提供了179.94 F g⁻¹，在40 A g⁻¹下经过10,000次循环后，电容保持率为77.5%，库仑效率为99.4%。电压保持和自放电研究证实了其优异的稳定性、低泄漏电流和最小的自放电。确定10 mg的PPD是理想浓度，在900 W kg⁻¹的功率密度下能够实现35.99 Wh kg⁻¹的能量密度。因此，结果强调了PPD混合凝胶聚合物电解质与NDAC之间的协同作用，是高性能超级电容器的理想组合。
