Abstract

This study systematically investigates seven metal-sulfur composite electrodes synthesized on nickel foam substrates via the Successive Ionic Layer Adsorption and Reaction (SILAR) method for supercapacitor applications. The seven different metal-sulfur composite electrodes—nickel-sulfur (Ni-S), chromium-sulfur (Cr-S), iron-sulfur (Fe-S), iron-nickel-sulfur (Fe-Ni-S), chromium-iron- sulfur (Cr-Fe-S), chromium-nickel-sulfur (Cr-Ni-S), and chromium-nickel-iron-sulfur (Cr-Ni-Fe-S) are all systematically investigated in this extensive study. The goal of the study is to use the synergistic effects of multi-metallic sulfide systems to further the development of high-performance supercapacitor electrodes. The structural and compositional characteristics of the synthesized electrodes were uncovered using a comprehensive set of characterization procedures. Transmission electron microscopy (TEM) shed light on the nanoscale architecture and crystallinity of the active materials, while scanning electron microscopy (SEM) demonstrated that the SILAR method produces homogeneous, nanostructured coatings with high surface area and interconnected porosity. X-ray photoelectron spectroscopy (XPS) demonstrated the presence of multiple oxidation states, confirming the coexistence of redox-active centers necessary for pseudocapacitive charge storage. In contrast, energy-dispersive X-ray spectroscopy (EDX) verified the uniform distribution of constituent elements across the electrode surface. Using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), and long-term cycle stability evaluations, electrochemical performance was thoroughly examined in a 1 M potassium hydroxide (KOH) electrolyte. By offering superior electrical conductivity, structural stability, and a sizable accessible surface area that promoted quick ion and electron movement, the nickel foam substrate significantly improved overall electrode performance. The most promising option among the electrodes under investigation was the chromium-nickel-iron-sulfur (Cr-Ni-Fe- S) composite. In the device arrangement, this electrode outperformed its single- and binary-metal counterparts with an impressive specific capacitance of 1441.60 F/g, an energy density of 21.08 Wh/kg, and a power density of 1034.33 W/kg. Notably, after 15,000 continuous charge-discharge cycles, the Cr-Ni-Fe-S electrode maintained 99.1% of its original capacitance, demonstrating exceptional electrochemical stability and highlighting its applicability for real-world energy storage applications. The synergistic interaction of many metal centers, which produces a rich network of complimentary redox pathways, improves electronic conductivity, and maximizes ion transport, is responsible for the Cr-Ni-Fe-S electrode's outstanding performance. In addition to demonstrating the critical role that multi-metal synergy plays in optimizing electrochemical performance, these results provide a strategic framework for the logical development of next-generation electrodes specifically suited for high-energy density supercapacitors. This discovery opens up new possibilities for the development of effective, long-lasting, and scalable energy storage technologies by providing a solid basis for future studies into sophisticated multi-component electrode systems

School

School of Sciences and Engineering

Department

Physics Department

Degree Name

MS in Physics

Graduation Date

Fall 7-17-2025

Submission Date

7-17-2025

First Advisor

Dr. Nageh Allam

Committee Member 1

Dr. Nageh Allam

Committee Member 2

Dr. Ahmed Hamed

Committee Member 3

Dr. Nacir Tit

Extent

71p.

Document Type

Master's Thesis

Institutional Review Board (IRB) Approval

Approval has been obtained for this item

Disclosure of AI Use

Thesis text drafting; Translation

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Available for download on Wednesday, September 22, 2027

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