Development of Graphitic Carbon Nitride-Encapsulated SrFe₂O₄ Spinel Nanocomposite Electrode for Enhancing Supercapacitor and Oxygen Evolution Applications

Abstract

In the past few years, there has been a notable upswing in the excitement surrounding bifunctional materials, primarily due to their versatility in accommodating energy storage and conversion needs. One class of materials that garnered considerable attention is strontium ferrite nanoparticles (NPs), which are known for their remarkable electrochemical properties stemming from their exceptional physical and chemical characteristics. In this study, we have synthesized a novel, cost-effective, and highly efficient composite electrode designed for dual functionality in supercapacitor (SC) and oxygen evolution reaction (OER) applications in alkaline environments. Herein, we prepared SrFe 2 O 4 @g-C 3 N 4 composite through a coprecipitation and pyrolysis method, resulting in featuring a porous g-C 3 N 4 matrix and strontium (Sr) spinel structure. The composite materials were thoroughly characterized using techniques such as powder Xray diffraction (XRD), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. The SrFe 2 O 4 @g-C 3 N 4 electrode exhibited outstanding pseudocapacitive behavior and delivered a specific capacitance of 1055 F/g at a current density of 1 A/g. Remarkably, it displayed a capacitance retention of 93% even after 5000 galvanostatic charge−discharge (GCD) cycles. Furthermore, in comparative assessments with bare SrFe 2 O 4 or g-C 3 N 4 electrodes, the SrFe 2 O 4 @g-C 3 N 4 composite electrode displayed superior and stable electrocatalytic performance. It required minimal overpotentials (only 170 mV) to achieve a current density of 10 mA cm −2 during the OER. These results emphasize the substantial potential of Sr-based nanocomposites as auspicious materials for applications in supercapacitors and as stable electrocatalysts.

Nitrogen-Doped Carbon Materials As Supercapacitor Electrodes: A Mini Review

“…Improving the capacitance of carbon materials can be achieved not only by controlling the design of their hierarchical pore structure but by introducing the electrochemically active sites on their surface and utilizing pseudocapacitance on top of the double-layer capacitance. − Common methods include the introduction of metal oxides or heteroatomic doping. , While the addition of metal oxides can offer more redox-active sites, issues are related to their accumulation that cannot be readily removed. Heteroatom doping involves inserting heteroatoms (e.g., N, P, S, B) into the carbon skeleton to create defect sites and functional groups connected to the carbon skeleton. , Oxygen reduction sites are introduced, to improve the wettability and electrical conductivity of pure carbon.…”

High-Performance Supercapacitor with Plasma-Assisted AlN and Graphitic Carbon Nitride Composite Electrode

“…The unique combination of high nitrogen content, thermal and chemical stability, wettability, ease of synthesis, and abundant raw materials makes graphitic carbon nitride a highly desirable material for a wide range of scientific and industrial applications, including photocatalysis, sensing, water splitting, and supercapacitors. − In energy storage, specifically in supercapacitors, g-CN serves as an effective electrode material. Its layered structure facilitates rapid ion transport, while the high nitrogen content provides pseudocapacitive contributions, enhancing the overall capacitance and energy storage capacity. − By amalgamating these two materials into a composite structure, the potential arises to harness their advantageous properties while mitigating individual shortcomings. g-CN has been the subject of extensive research, extending its utility to diverse applications such as photocatalysis, CO 2 reduction, hydrogen production, and metal-air batteries, owing to its superior thermal and chemical stability, mechanical robustness, and elevated nitrogen content. , However, g-CN grapples with intrinsic limitations, including low electrical conductivity and a limited surface area, restricting its electrochemical applications. , Efforts to overcome these challenges have been undertaken, for instance.…”