CoFe2O4 Hollow Spheres-Decorated Three-Dimensional rGO Sponge for Highly Efficient Electrochemical Charge Storage Devices

Current insights and future prospects of graphene aerogel-enhanced supercapacitors: A systematic review

Supercapacitors present a compelling alternative to conventional batteries, offering rapid energy storage and high power density. Despite their advantages, they typically fall short in energy density compared to traditional batteries, primarily due to limitations in electrode materials. Graphene Aerogels (GA) have emerged as a promising solution to enhance supercapacitor performance because of their unique properties, such as high surface area and excellent conductivity. This systematic review provides a comprehensive analysis of recent advancements in GA technology, focusing on their synthesis methods and applications in supercapacitors. It highlights significant improvements that GA can bring to Electric Double-Layer Capacitors (EDLCs), pseudocapacitors, and hybrid supercapacitors. Additionally, the review explores GA's potential for enhancing electric generators and integrating into flexible, wearable technologies. Future research directions are emphasised, particularly regarding GA's potential applications in waste management and environmental protection. The review was conducted through a thorough literature search, prioritising peer-reviewed sources related to GA synthesis and supercapacitor applications. Methodological quality and potential biases of the included studies were assessed using principles similar to the Cochrane Risk of Bias tool. Thematic analysis was employed to synthesise findings and identify key trends and challenges. Limitations such as potential biases and methodological variations are discussed. Overall, this review highlights the technological prospects of GA and provides guidance for future research in supercapacitor development and applications.

Application of dandelion-like Sm2O3/Co3O4/rGO in high performance supercapacitors

Novel 2D material-based supercapacitors are promising candidates for energy applications due to their distinctive physical, chemical, and electrochemical properties. In this study, a dandelion-like structure material comprised of Sm2O3, Co3O4, and 2D reduced graphene oxide (rGO) on nickel foam (NF) was synthesised using a hydrothermal method followed by subsequent annealing treatment. This dandelion composite grows further through the tremella-like structure of Sm2O3 and Co3O4, which facilitates the diffusion of ions and prevents structural collapse during charging and discharging. A substantial number of active sites are generated during redox reactions by the unique surface morphology of the Sm2O3/Co3O4/rGO/NF composite (SCGN). The maximum specific capacity the SCGN material achieves is 3448 F g-1 for 1 A g-1 in a 6 mol L-1 KOH solution. Benefiting from its morphological structure, the prepared composite (SCGN) exhibits a high cyclability of 93.2% over 3000 charge-discharge cycles at 10 A g-1 and a coulombic efficiency of 97.4%. Additionally, the assembled SCGN//SCGN symmetric supercapacitors deliver a high energy density of 64 W h kg-1 with a power density of 300 W kg-1, which increases to an outstanding power density of 12 000 W kg-1 at 28.7 W h kg-1 and long cycle stability (80.9% capacitance retention after 30 000 cycles). These results suggest that the manufactured SCGN electrodes could be viable active electrode materials for electrochemical supercapacitors.

Facile Synthesis of Hollow Fe3O4-rGO Nanocomposites for the Electrochemical Detection of Acetaminophen

Acetaminophen (AC) is one of the most popular pharmacologically active substances used as an analgesic and antipyretic drug. Herein, a new type of hollow Fe₃O₄-rGO/GCE electrode was prepared for electrochemical detection of AC through a three-step approach involving a solvothermal method for the synthesis of hollow Fe₃O₄ and the chemical reduction of graphene oxide (GO) for reduced graphene oxide (rGO) and Fe₃O₄-rGO nanocomposites modified on the glassy carbon electrode (GCE) surface. The as-prepared Fe₃O₄-rGO nanocomposites were characterized using a transmission electron microscope (TEM), X-ray diffraction (XRD), and a magnetic measurement system (SQUID-VSM). The magnetic Fe₃O₄-rGO/GCE electrodes were employed for the electrochemical detection of AC using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV) and exhibited an ultra-high selectivity and accuracy, a low detection limit of 0.11 µmol/L with a wider linear range from 5 × 10^-7 to 10^-4 mol/L, and high recovery between 100.52% and 101.43%. The obtained Fe₃O₄-rGO-modified GCE displays great practical significance for the detection of AC in drug analysis.

CoFe2O4 Nanoparticles Grown within Porous Al2O3 and Immobilized on Graphene Nanosheets: A Hierarchical Nanocomposite for Broadband Microwave Absorption

Demands to develop efficient microwave-absorbing materials are increasing with the advancement of information technology and the exponential rise in the usage of electromagnetic devices. To reduce electromagnetic interference and to overcome the adverse effects caused by microwave exposure resulting from the excessive usage of electromagnetic devices, microwave absorbers are very necessary. In addition, radar-absorbing materials are essential for stealth technology in military applications. Herein, we report a nanocomposite in which CoFe₂O₄ (CF) nanoparticles were grown within the porous structure of Al₂O₃ (PA), and this CoFe₂O₄-loaded Al₂O₃ (PA-CF) nanocomposite was immobilized on the surface of nanometer-thin graphene sheets (Gr). Owing to the hierarchical structure created by the constituents, the (60PA-40CF)₉₀-Gr₁₀ nanocomposite exhibited excellent microwave-absorption properties in the X-band region with a reflection loss (RL) value of ∼-30.68 dB (∼99.9% absorption) at 10.71 and 9.04 GHz when thicknesses were 2.0 and 2.3 mm, respectively. This nanocomposite demonstrated its competence as a lightweight, high-performance microwave absorber in the X-band region, which can be utilized in the applications of pioneering stealth technology.