In the past few years, significant research efforts have been directed toward improving the electrochemical capabilities of supercapacitors by advancing electrode materials. The present work signifies the development of poly(lactic acid)/alloysite nano-clay as an electrode material for supercapacitors. Physico-chemical characterizations were analyzed by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, and a universal testing machine. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge techniques were employed to evaluate electrochemical characteristics. The optimized poly(lactic acid)/halloysite nano-clay film revealed the highest specific capacitance of 205.5 F g⁻¹ at 0.05 A g⁻¹ current density and showed 14.6 Wh kg⁻¹ energy density at 72 W kg⁻¹ power density. Capacitance retention of 98.48% was achieved after 1000 cycles. The microsupercapacitor device presented a specific capacitance of 197.7 mF g⁻¹ at a current density of 0.45 mA g⁻¹ with 10.8 mWh kg⁻¹ energy density at 549 mW kg⁻¹ power density.

Modified biochar (BC) nano-compounds are very promising candidates for the accelerated degradation of reoccurring contaminants in wastewater treatment. The surface activity, structural repair, and dopant chemistry of biochar determine its adsorption ability and catalytic behaviour. Metal oxides such as Fe₃O₄ and FeS₂ offer fast electron-transfer pathways that accelerate the redox-mediated transformations of heavy metal ions, while surface-engineered functional groups, particularly phosphorus moieties and EDTA ligands, provide tunable coordination environments that significantly enhance selectivity toward Pb²⁺ and Ni²⁺. Chemical activators such as ZnCl₂ and KOH introduce hierarchical porosity and widen the distribution of adsorption sites, thereby improving the reactant accessibility and charge-transfer efficiency. Layered double hydroxides (Ni–Fe and Mg–Al) exhibit structurally defined anion-exchange galleries that preferentially interact with oxyanions (PO₄ ³⁻ and NO₃ ⁻), whereas heteroatom-doped biochars (S/N-BC) generate polarized electron densities favourable for binding soft metal ions such as Hg²⁺ and Cu²⁺. Additionally, carbonaceous nanostructures (CNTs and graphene oxide) enable π–π stacking and delocalized electron mediation for the sensitive detection and transformation of aromatic dye molecules. From a materials chemistry perspective, the innovation lies in tailoring these nano-hybrids at the atomic-to-nano scale, optimizing their mechanical stability, interfacial charge dynamics, and metal–support interactions while comprehensively evaluating their structural persistence and catalytic fidelity under realistic aqueous reaction conditions. AI-directed designs aid in performance optimization. Finally, identifying research gaps, optimizing benefit circulation, and conducting comprehensive life cycle assessment (LCA) are crucial for the effective implementation of these concepts. In this review, these aspects are systematically discussed and highlighted to guide future research directions for the next generation of studies.

The current work is motivated by the rising applications of value-regulated lead acid (VRLA) batteries. The performance of VRLA batteries depends on the type of electrolyte used. The gel electrolyte is an important factor that controls both the manufacturing process and the performance of VRLA batteries. We formulate polymer gel electrolytes composed of sodium alginate (NaAlg) with varying amounts of montmorillonite (MMT). The nature of gel electrolytes is analyzed by Fourier transform infrared (FTIR) spectroscopy, the ionic conductivity study and the water retention study. The gel electrolytes are subjected to electrochemical characterization methods like cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). 2 wt% MMT@NaAlg shows better electrochemical performances. Galvanostatic charge–discharge (GCD) tests are performed on optimized gel electrolytes, and display a maximum discharge capacity of 138 μA h cm⁻² at a current density of 0.55 mA cm⁻². The prototype battery shows a maximum discharge capacity of 2.8 × 10⁻⁶ A h at a current density of 35 μA cm⁻². After 500 cycles, the battery accomplishes 89% discharge capacity. NaAlg-based gel electrolytes with additives can be used for the manufacturing of VRLA batteries.

The gel electrolyte significantly influences gel valve-regulated lead acid battery performance. To address this, the paper describes the preparation of novel polymer gel electrolytes using poly (vinyl alcohol) (PVA) and tetraethylorthosilicate (TEOS) for valve-regulated lead–acid batteries. FTIR technique is used to confirm the chemical reaction between PVA and TEOS. Electrochemical analyses such as cyclic voltammetry and electrochemical impedance spectroscopy were applied to optimize the concentration of PVA-TEOS polymer gel electrolyte. The optimum concentration of polymer gel electrolyte was determined as 20 wt% of TEOS in PVA (PE-1) with higher anodic peak and lower Rs and Rct values. The Galvanostatic charge–discharge tests were performed on the optimized gel system prototype battery. The highest capacity of 6.86 × 10⁻⁵ Ah at a current density of 0.2 mA cm⁻² was achieved with an excellent capacity retention ratio of 85.7% over 500 cycles. The exceptional cycle performance and high capacity make PVA-TEOS gel electrolyte a promising candidate for practical battery application.

The performance of electrochemical supercapacitors is greatly affected by electrodes, which are considered one of the most significant components. This article sheds light on manganese dioxide (MnO₂)-incorporated poly(methyl methacrylate) (PMMA) membranes as electrodes for supercapacitor applications. The interaction between MnO₂ and PMMA is justified by Fourier transform infrared spectroscopy. The surface morphology of MnO₂@PMMA membranes was observed using scanning electron microscopy and atomic force microscopy. Techniques such as cyclic voltammetry and electrochemical impedance spectroscopy indicated that a 7.5 wt% MnO₂@PMMA membrane exhibited the highest electrochemical performance. GCD tests revealed that the 7.5 wt% MnO₂@PMMA membrane showed a maximum specific capacitance of 361 F g⁻¹ at a current density of 125 mA g⁻¹ with a maximum energy density of 144 W h kg⁻¹ and maximum power density of 1135 W kg⁻¹. The membrane displayed 87% capacitance retention after 5000 cycles. The fabricated interdigital microsupercapacitor device revealed the highest specific capacitance of 528 mF g⁻¹ at a current density of 0.15 mA g⁻¹ with a maximum energy density of 47 mW h kg⁻¹ and maximum power density of 400 mW kg⁻¹.