Kumaran Vediappan

Fire hazards pose a major challenge to wooden structures worldwide due to wood's inherent flammability and rapid flame spread, underscoring the urgent need for innovative materials and strategies to enhance fire resistance. In this context, a novel non‐covalent integration strategy was developed using pyridine‐substituted cyclotriphosphazene derivatives with Keggin‐type heteropoly tungstate anions ([PW ₁₂ O ₄₀ ] ³⁻ ), yielding multifunctional POM(W)–PN‐DP, POM(W)–PN‐TP, and POM(W)–PN‐HP materials with flame‐retardant and electrochemical properties. When incorporated into epoxy and applied to wood, the 10 wt% EP/POM–PN composite achieved a UL‐94 V‐0 rating and an LOI above 24 vol%, demonstrating enhanced fire resistance and mechanical strength through a synergistic P/N effect. Cone calorimeter tests further revealed significant reductions in both the total heat release rate and peak heat release rate. The synergistic interactions among POM(W)–PN‐DP and POM(W)–PN‐HP promoted the formation of a stable protective char layer during the combustion. Furthermore, the electrochemical performance of the synthesized materials was evaluated for supercapacitor applications using a standard three‐electrode system. POM(W)–PN‐HP and POM(W)–PN‐TP showed superior performance, with specific capacitances of 227.4 and 143.2 F/g, respectively, at 1 A/g. These POM–PN hybrids represent a promising class of multifunctional additives for fire‐safe and electrochemically active polymer systems.

Inorganic fillers are widely employed in solid polymer electrolytes to regulate the coordination environment, Lewis acidity, and interfacial reactivity. Among them, borate-based fillers are particularly attractive due to their dual Lewis acidic sites and strong affinity toward oxygen-containing ligands. However, in poly(vinyl alcohol) (PVA)-based electrolytes, zinc borate (ZB) fillers readily form reversible borate ester linkages with PVA hydroxyl groups, passivating Lewis acid sites and limiting filler functionality. Herein, to overcome the situation and to improve the performance of the filler, competitive esterification, cross-linking, and solvent coordination are employed. Citric acid (CA) cross-linking preferentially consumes PVA hydroxyl groups and modifies PVA–ZB interactions, potentially increasing the availability of borate-associated Lewis acidic sites. A subsequent solvent exchange with diethyl carbonate replaces the coordinated water molecules, further stabilizing the borate-coordination framework. Spectroscopic and electrochemical analyses confirm the cross-linking and solvent coordination, correlating with enhanced ionic conductivity and interfacial stability. A stable lithium plating-stripping reaction with very low polarization potential provides evidence of uniform interfacial lithium deposition. While extended cycling reveals gradual capacity decay associated with inorganic-rich interphase formation, the study highlights the critical role of coordination chemistry and the solvent environment in governing the functionality of borate fillers in polymer matrices.

The gravimetric and volumetric penalties associated with metallic zinc anodes motivate the development of metal-free zinc-ion architectures. However, the interfacial chemistry governing their operation remains poorly understood, particularly across distinct solvation environments. Here, we investigate how electrolyte anion chemistry in aqueous ZnSO4 and nonaqueous Zn(Otf)2/acetonitrile electrolytes influences the solvation structure, interface composition, and charge transfer kinetics in a zinc-ion capattery employing an interstitially engineered zinc vanadate cathode and a hard carbon anode. MD simulations reveal fundamentally different primary solvation structures: strongly hydrated [Zn(H2O)6]2+ complexes in aqueous media and mixed acetonitrile-triflate coordination in nonaqueous systems. These differences translate into distinct interfacial chemistries. In the aqueous electrolyte, interfacial hydroxylation dominates, leading to a dynamically evolving, redox-active cathode electrolyte interface. In contrast, triflate-rich solvation promotes the formation of a fluorinated organic–inorganic interface composed of ZnF2 and cyano-derived species, generating a stable, ion-permeable barrier. State-of-charge-resolved impedance spectroscopy correlates these interface architectures with diffusion-controlled kinetics in aqueous systems and stabilized charge transfer in nonaqueous media. Together, these findings establish a mechanistic link between anion-governed solvation structure and the emergent interfacial architecture, providing a framework for electrolyte design in metal-free zinc-ion energy storage.

Gel-based routes, particularly sol–gel processes, offer a versatile pathway to generate uniform inorganic networks and gel-derived functional ceramics with controlled composition and interfacial coverage. In this study, we employ a citrate-assisted sol–gel coating strategy to form a precursor gel containing Li, La, Zr, and Ge species on lithium-rich manganese-based layered oxide (LMLO) cathode particles, followed by drying/thermal conversion to obtain a Ge-substituted garnet-type Li₇La₃Zr₂O₁₂ (Ge-LLZO) ceramic coating. Structural and surface analyses (FE-SEM/EDS, XPS, and FE-TEM) confirm the presence of surface-deposited coating-related species and coating-induced changes in surface chemistry, while bulk XRD is primarily used to verify that the layered LMLO host structure is preserved after the gel-to-ceramic treatment. Electrochemical testing indicates that the gel-derived Ge-LLZO coating can influence interfacial kinetics and resistance evolution, as reflected by differential capacity behavior, impedance responses, and rate capability trends, alongside microstructural observations suggesting reduced damage compared with bare LMLO after cycling. Overall, this work demonstrates that gelation-assisted deposition and gel-to-ceramic conversion enable Ge-LLZO surface coatings on LMLO cathodes that modulate interfacial kinetics and resistance evolution. Under the harsh 4.8–2.0 V/1C condition, the bare LMLO shows an abrupt capacity drop after ~60 cycles, while the coated LMLO exhibits a more gradual decay up to 100 cycles; further optimization is required for robust long-term stability.

This review reveals the parameters of next-generation fuel cells for portable applications such as cellular phones, laptops, automobiles, etc. Disputes over issues such as design, fluid dynamics, channel dimensions, thermal management, and water management must be overcome for practical applications. We examine techniques such as microfabrication, material selection for membranes and electrodes, and integration challenges in small-scale devices, in addition to issues like methanol crossover, low efficiency at high methanol concentrations, thermal management, and the cost of materials. The advancements in micro-DMFC stacks and prototype developments are presented, and the challenges relating to micro-DMFCs are also identified and reviewed in detail. The challenges in the development of micro-DMFC applications are also presented, including the need for a better understanding of the anode and cathode catalyst structure and for high catalyst loadings in oxidation-and-reduction reactions. Also, a comprehensive and highly valuable database for advancing innovations and enhancing the understanding of micro-DMFCs for potential applications is provided.

The primary concern of interest in high-voltage cathodes such as spinel LiMn2O4 is transition metal dissolution. Though several techniques and structural modifications are continuously under examination, a crucial factor that could make a significant impact is the careful evaluation of electrolyte properties. In this regard, a PVA/TiO2 (PT) quasi-solid polymer electrolyte prepared using an electrospinning technique is employed to suppress HF scavengers, a main cause of manganese dissolution. Good electrochemical stability of 5.05 V, ionic conductivity of 0.26 × 10–5 S cm–1, stable plating–stripping, and tLi+ of 0.82 are evidence for good electrolyte performance. Lewis acid sites of TiO2 firmly hold the PF6– anions, and strong hydrogen bonding of carbonate solvents disrupts the cycle of electrolyte decomposition reactions. The capacity retention of 73% after 500 cycles at a 2C rate and post-mortem analysis of the LMO cathode provide evidence for the successful suppression of manganese dissolution using a PT electrolyte.

This work explores polyanionic phosphate-type α-Zn3(PO4)2 (ZP) as a negative electrode in lithium-ion batteries. It has a high theoretical capacity of 278 mA h g−1. The crystal structure of ZP is elucidated, and Patterson's electron density profiling is performed to understand the possible site of lithiation. To address the polaron-driven electrical insulation common to phosphates, we use superficial carbon coating (ZP/C). Furthermore, the electrochemical analysis of ZP and ZP/C is performed to validate the half-cell performance and Li+ kinetics. ZP/C delivers a high capacity of 260 mA h g−1 at 0.1 C. The positive effect of carbon coating is evident from a 100-fold increase in lithium diffusion coefficient from the galvanostatic intermittent titration technique. In addition, temperature-driven capacity performance is analyzed at −10, 25, and 50 °C. Temperature gradient charge–discharge is performed between −10 and −5 °C, where the discharge capacity increases from 70 to 100 mA h g−1 at 1 C rate, extending the application toward low-temperature non-carbonaceous energy storage solutions.