Modern electrochemical energy storage devices, such as supercapacitors, require advanced electrode architectures to achieve superior energy densities and rapid kinetics. Here, nickel-doped molybdenum disulfide MoS2 nanoparticles (2
Polyaniline-coated MgCo2O4 (denoted as P@MCO) was synthesized via a two-step process consisting of hydrothermal preparation of MgCo2O4 followed by chemical oxidative polymerization of aniline. The structural, morphological, and chemical properties of the prepared materials were characterized using XRD, FTIR, XPS, TEM-EDS, BET, and TGA analyses. The electrochemical performance was evaluated in a three-electrode system using 3.0 M KOH electrolyte through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The P@MCO electrode exhibited a specific capacitance of 141.93 F.g− 1 at a current density of 0.1 A.g− 1, compared with 69.04 F.g− 1 for pristine MCO. After 10,000 charge–discharge cycles, P@MCO retained 88.71
Transition-metal phosphide (TMP)/carbon nanocomposites have garnered significant interest as potential electrode materials for high-performance supercapacitors due to their advantages, including high electrical conductivity, abundant redox activity, and structural adaptability. Nonetheless, despite several reports of improved electrochemical performance, a review that provides synthesis-structure-property relationships, performance limitations, and design principles is still lacking. Therefore, this review offers a thorough, critical examination of TMP/carbon composites for supercapacitor applications, highlighting the interplay among charge storage mechanisms, synthesis-structure-property relationships, and practical performance. This review re-evaluates the charge-storage characteristics of TMP/carbon systems beyond the traditional electrical double-layer capacitance and pseudocapacitance paradigm, emphasizing the simultaneous presence of surface-controlled and diffusion-limited processes and their common misidentification. The functions of the TMP electronic structure, metal–phosphorus bonding, and carbon-mediated interfacial charge transfer are analysed in detail to establish a mechanistic basis. We then examine the impact of synthesis techniques on morphology, phase composition, porosity, and interfacial coupling from a structure-property viewpoint. An incisive assessment of documented electrochemical performance reveals significant shortcomings in the literature, including exaggerated capacitance values, unrepresentative test conditions, and a lack of standardised benchmarking methodologies. Furthermore, significant degradation mechanisms, including mechanical instability, loss of electrical conductivity, electrolyte incompatibility, and interfacial degradation, are analysed to elucidate long-term performance constraints. In light of these findings, this review recommends a series of design concepts for next-generation TMP/carbon supercapacitors, encompassing electronic optimisation, structural engineering, interfacial management, and device-level factors. This review presents a cohesive, mechanism-based framework that links material design to electrochemical performance and offers direction for creating robust, high-performance, and scalable energy storage devices.
Aqueous zinc-ion batteries (AZIBs) have emerged as an excellent choice in rechargeable batteries due to their low redox potential, large volumetric capacity, and cost-effectiveness. However, the development of durable and efficient cathode materials with promising practical capacity remains a challenge. Here, nitrogen-doped reduced graphene oxide-silver vanadate (NrGO-AVO) composite was synthesised via a hydrothermal process and utilised as a cathode for AZIB. Comprehensive structural, morphological, thermal and electrochemical characterisations, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectrum, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), Galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) were carried out. The incorporation of NrGO significantly boosted the overall performance by increasing active site accessibility and thus improving charge-transfer kinetics with efficient electron transport during charge-discharge operations. The NrGO-AVO//Zn AZIB delivered a specific capacity of 178 mAh g− 1 at 1 C, and appreciable cyclic stability over 500 cycles. A Zn²⁺ diffusion coefficient of the order of 10− 9 cm² s⁻¹ was found for NrGO–AVO by galvanostatic intermittent titration technique (GITT) analysis, which was in the order of 10− 10 for pure AVO, suggesting favourable Zn²⁺-transport kinetics of the composite. Furthermore, the cell attained a specific energy of 151 Wh kg⁻¹ at a specific power of 195 W kg⁻¹. Additionally, a post-mortem study was performed for NrGO-AVO//Zn AZIB after cycling performance using XRD, FESEM, and EDAX analysis. These results show that the NrGO–AVO composite is a suitable cathode material for aqueous zinc-ion batteries.
Efficient energy storage is crucial for advancing renewable energy technologies. Supercapacitors, with their higher power density and improved cycle life than traditional batteries, are attractive as in many applications. This study investigates CeO2/rGO as a hybrid electrode material, combining the electrochemical activity of CeO₂ with the high electrical conductivity and large surface area of reduced graphene oxide. The novelty of this work lies in the finite-element simulation of the CeO₂/rGO hybrid electrode, incorporating ion diffusion and interfacial charge-transfer kinetics to elucidate its simulated electrochemical behaviour. The electrochemical behaviour and cyclic voltammetry (CV) performance are simulated for a two-dimensional supercapacitor structure using a finite element modelling software. The model evaluates ion diffusion and charge transfer kinetics, providing insights into how the composite’s structure enhances hybrid capacitive performance for advanced electrochemical energy storage systems. The electrochemical performance of the simulated CeO2/rGO composite demonstrates potential for supercapacitor applications. CV profiles show quasi-rectangular geometries, indicating electric double layer capacitance (EDLC) behaviour and pseudocapacitive contributions. The electrode achieves a peak areal capacitance of 2758.7 mFcm− 2 and a specific capacitance of 511.30 Fg− 1. The system shows good rate capability with the capacitance retention of 71 μ Whcm− 2 and power density of 58 mWcm− 2 is achieved. These results confirm that the synergistic effect of CeO2/rGO ensures efficient charge transport and high-power delivery.
