Developing oxygen evolution reaction (OER) catalysts in acidic electrolyte with both high activity and stability remains a major challenge for large-scale deployment of proton exchange membrane water electrolysis (PEMWE). Particle agglomeration is inevitable for catalysts synthesized by the conventional Adams fusion method or the impregnation-reduction approach. In this work, a novel dual-template synthesis method has been adopted to prepare Ir0.3Ru0.7Ox with a three-dimensional porous architecture. Ir0.3Ru0.7/C is synthesized by chemical reduction, followed by calcination with a large amount of inorganic salt (NaCl), in which the evolution of gaseous carbon dioxide (carbon itself is sacrificed) results in voids and NaCl (which is washed away as filtrate) provides physical separation at high temperature, preventing catalysts from sintering and facilitating pore formation. The as-prepared Ir0.3Ru0.7Ox exhibits an overpotential of 303 mV at 10 mA cm−2 and a mass activity of 1.13 A mg−1oxide at 1.6 V. The introduction of dual templates effectively reduces the catalyst particle size, thereby enabling Ir0.3Ru0.7Ox with enhanced OER activity as well as good stability. This work offers an effective and general strategy for the rational design and development of catalysts for PEMWE applications.
Fossil fuels pose significant environmental challenges, driving the shift toward sustainable energy alternatives. Green hydrogen is a key component of the global energy transition, with alkaline electrolysers being the most mature technology for hydrogen production. This study examines the relationship between hydrogen production rates and electrolyte concentrations (10–35%) in a laboratory-scale alkaline electrolyser. Six electrolytes are evaluated: NaOH, NaOH–NaCl, NaOH–NH3, NaOH–NPK, NaOH–NaHCO3, and KOH. Infrared thermography is used to analyse thermal behaviour and its correlation with gas collection at cathode by measuring the temperature difference (ΔT) across concentrations. Results show that NaOH–NaCl at 10% achieves the highest apparent gas collection at cathode of 5.324 mL/s with ΔT = 13.9 °C at this concentration. Thermal analysis reveals that pure NaOH exhibits the strongest thermal response, reaching 61.5 °C at 35%, while KOH reaches 57.4 °C. Adding NPK fertilizer to NaOH significantly enhances production, reaching 2.895 mL/s at 10% and improving by 512.43% at 35%. Likewise, the NaOH–NH3 system shows a 273.39% increase gas collection at cathode with rising concentration. Polynomial regression models are developed to describe the relationship between concentration and flow rate. This work identifies optimal electrolyte compositions and concentrations for maximizing hydrogen generation through systematic electrolyte optimization.
Aqueous zinc–iodine (Zn–I2) batteries are promising for safe and cost-effective energy storage, but their durability is limited by nonuniform Zn deposition at the anode and polyiodide shuttling from the cathode. Here, mycelium-leather alternative waste (MLAW) was converted by chitinase-assisted hydrolysis into a chitin-oligosaccharide-rich (COS-rich) hydrolysate and immobilized on a commercial glass-fiber (GF) scaffold to form an organic–inorganic hybrid separator. The resulting CMLW-500/GF interphase combines a densified transport pathway with abundant hydroxyl, amino, and acetamido groups. Spectroscopic and morphological analyses indicate that these functionalities promote polyiodide retention and provide coordination sites for regulating hydrated Zn2+ transport. Accordingly, the modified separator suppresses rough Zn deposition and decreases the interfacial charge-transfer resistance from 135.1 to 50.9 Ω. Kinetic analysis indicates rapid interfacial Faradaic conversion of confined polyiodide species. Zn–I2 cells using CMLW-500/GF retain 99.0% of their capacity after 3000 cycles at 1 A g−1 and operate for 11,000 cycles at 5 A g−1 while maintaining a capacity of approximately 160 mAh g−1 and nearly 100% Coulombic efficiency. This work demonstrates a practical route for converting fungal-material waste into a multifunctional separator interphase that concurrently mitigates Zn-anode instability and polyiodide crossover.
Spinel ferrites MgFe2O4 possess multiple oxidation states and tunable redox activity, making them attractive pseudocapacitive electrode candidates. Phase-pure MgFe2O4 nanoparticles are synthesized via a facile urea-assisted solution combustion method and evaluated as pseudocapacitive electrode materials. XRD confirmed a cubic spinel structure (Fd3m, crystallite size 22.38 nm). BET analysis revealed a specific surface area of 34.7 m2g-1 with a mesoporous pore-size distribution (average pore diameter 11.4 nm). XPS confirmed coexisting Fe2+/Fe3+ redox states. In a three-electrode cell (2 M KOH), the MgFe2O4 electrode delivered a high specific capacitance (Csp) of 563 F g−1 at 0.1 A g−1, energy density (E) of 19.6 Whkg−1 at a power density (P) of 46.9 Wkg-1, along with 75.82% capacitance retention over 10,000 cycles (90.10% coulombic efficiency). This Csp is substantially higher than several previously reported MgFe2O4 electrodes obtained by hydrothermal (240 F g−1), sol-gel (438.9 F g−1), and co-precipitation (298 F g−1). A symmetric two-electrode cell yielded a Csp of 151.25 F g−1, E of 5.25 Whkg−1, and P of 156.25 Wkg−1. The enhanced performance is attributed to the porous nanoarchitecture, large active surface area, mixed Fe2+/Fe3+ redox activity, thereby establishing urea-assisted combustion-derived MgFe2O4 as a promising, cost-effective pseudocapacitive electrode material for next-generation supercapacitors.
Silicon (Si) is a highly promising anode material for next-generation lithium-ion batteries, yet its practical electro-performance is severely hindered by massive volume changes and unstable solid electrolyte interphase (SEI) film. Herein, we introduce a simple and cost-effective strategy to address these challenges by modifying a Si-Carbon (Si-C) composite with sodium monofluorophosphate (SMFP, a low-cost and environmentally friendly additive with high ionic conductivity). During sintering at 650°C (above the melting point of SMFP, 625°C), the melted SMFP diffuses into the Si-C particles and coats on the surface, thus could not only suppress the side reactions between Si and electrolyte but also behave as an artificial SEI film to diminish the consumption of electrolyte and Li-ions for improving initial Coulombic efficiency (ICE). The optimized SMFP-modified anode (Si-C@0.5SMFP) demonstrates significantly enhanced electrochemical performance, delivering an ICE of 84.08% and retaining a capacity of 450.7 mAh g−1 after 500 cycles at 2 A g−1, substantially outperforming the pristine Si-C. Mechanistic investigations reveal that the superficial SMFP could protect the Si-C anode from continuous electrolyte decomposition and boost Li-ion diffusion kinetics. This work presents a scalable and economical approach to stabilize Si-based anodes, offering a promising pathway for developing the lithium-ion batteries with high-energy-density.
Polydimethylsiloxane (PDMS) is a promising fluorine-free hydrophobic material for proton exchange membrane fuel cell (PEMFC) microporous layers (MPLs) owing to its low surface energy, environmental compatibility, and low-temperature curing. However, weak adhesion between low-loading PDMS and carbon materials limits the structural stability, especially under hydrothermal and oxidative conditions. Here, 3-aminopropyltriethoxysilane (APTES) is used to modify carbon black and enhance the carbon-PDMS interfacial interaction. An APTES-modified 5 wt% PDMS-MPL is compared with unmodified 5 wt% PDMS-MPL and conventional 20 wt% polytetrafluoroethylene (PTFE)-MPL. Hot-water and Fenton oxidative aging, combined with microstructural, pore, hydrophobicity, X-ray photoelectron spectroscopy (XPS), and single-cell electrochemical analyses, are used to evaluate aging-induced degradation and transport evolution. APTES modification reduces the ultrasonic mass loss rate from 11.67% to 5.17%, indicating improved interfacial stability. After aging, the modified MPL maintains a more stable pore structure and hydrophobicity and shows a mass-transfer resistance of 0.194 Ω cm2 after Fenton aging. In contrast, unmodified PDMS-MPL exhibits polymer migration, local delamination, and oxidation, whereas PTFE-MPL retains a relatively stable pore structure but shows stronger high-current mass-transport limitations. These results demonstrate that APTES interfacial modification improves the structural stability and aging resistance of low-loading fluorine-free PDMS-based MPLs.
High-voltage lithium metal batteries with high energy densities (>450 Wh kg−1) are widely regarded as promising candidates for next-generation rechargeable energy storage systems. However, their practical implementation is substantially hindered by the inadequate interfacial stability of conventional electrolytes. Herein, we leverage strong dipole-dipole interactions induced by non-coordinating solvent ethoxy(pentafluoro)cyclotriphosphazene (PFPN) to modulate the Li+ solvation structures of fluorinated carbonate electrolyte, thereby enhancing electrode/electrolyte interfacial stability. The dipole-dipole interaction between PFPN and fluorinated carbonate solvents effectively weakens solvent-Li+ coordination, facilitating increased anion participation in the primary solvation shell of Li+. This restructured solvation environment promotes the formation of robust anion-derived LiF-rich solid electrolyte interphases (SEIs) and cathode electrolyte interphases (CEIs) at both electrodes, substantially improving interfacial stability of lithium metal anodes and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes. As a result, Li||NCM811 cells incorporating this electrolyte demonstrate exceptional cycling stability, retaining 80.8% of their initial capacity after 700 cycles. Furthermore, the cells exhibit markedly enhanced performance under harsh operating conditions, including high cut-off voltages (4.5 V) and elevated temperatures (60 °C). This study offers new insights into electrolyte engineering through targeted manipulation of intermolecular interactions, providing a viable pathway toward the development of high-performance lithium metal batteries.
Parasitic hydrogen evolution and anodic dissolution block practical deployment of aluminium–air batteries. The reported inhibition efficiency values are not comparable across studies: corrosion current densities span 2 to 456 μA cm−2 and hydrogen evolution rates span 0.042 to 1.317 mL min−1 cm−2, with alloy grade, NaOH concentration, and current density inconsistently reported across laboratories. This review assesses conventional and advanced diagnostic techniques for Al-air corrosion. Tafel polarization, electrochemical impedance spectroscopy, and volumetric H2 measurement serve as macroscopic screening tools; EQCM-D, SECM, DRT, XPS, ToF-SIMS, and TEM/Cryo-TEM provide spatially and chemically resolved operando data. Working principles, battery applications, and compatibility constraints with 4 M NaOH are discussed for each technique. Documented case studies on Zn and Al interfaces anchor the recommendations. A six-criteria assessment shows that Al-air compatibility, not technique capability, is the binding limitation for every advanced method: H2 bubbles disrupt SECM tip feedback, EIS non-stationarity restricts DRT deconvolution to inhibited, quasi-stationary anodes, and vacuum transfer degrades XPS/TEM film chemistry. Three research priorities follow: standardized discharge protocols to enable cross-laboratory comparison, operando instrumentation adapted to alkaline conditions, and hybrid inhibitor molecules combining bulk water-activity modifiers (glycerol, sorbitol) with surface-adsorbing heteroatom-rich compounds to block both electrochemical and non-faradaic corrosion pathways.
Hot-pressing is a critical yet insufficiently understood step in the fabrication of membrane electrode assemblies (MEAs) for proton exchange membrane fuel cells (PEMFCs). Here, a design-of-experiments approach based on a Central Composite Rotatable Design (CCRD) is employed to decouple the effects of temperature, pressure, and compression time in catalyst-coated substrate MEAs. Strong non-linear interactions between processing parameters are identified, highlighting the limitations of conventional optimization strategies. Optimal conditions (144°C, 5.0 MPa, 2.1 min) yield a peak power density of 1055 mW cm−2 under H2/O2 at 95% relative humidity, with excellent agreement between predicted and experimental values (∼1% error). Morphological analysis using SEM reveals qualitative differences in interfacial morphology between higher- and lower-performing MEAs, consistent with a possible contribution of interfacial quality to performance. The response-surface framework proved applicable under reduced humidity and air operation, with distinct optimal hot-pressing parameters identified for each condition, confirming that MEA fabrication must be specifically optimized for the targeted operating environment. Optimal hot-pressing parameters were found to be system-dependent. This work establishes a predictive framework for scalable and reproducible fabrication of high-performance PEMFC MEAs.
