Selective transport of chemically similar monovalent ions remains a major challenge in membrane-based separations. This study demonstrates that defect engineering in UiO-66 membranes can effectively regulate ion permeation by varying the average number of missing-linker defects. Electrochemical measurements revealed that the ion permeation sequence shifted from K+ > Na+ > Li+ in low-defect UiO-66 to Li+ > Na+ > K+ in moderately defective membranes and reverted to K+ > Li+ > Na+ in highly defective frameworks. Mixed-ion permeation tests further confirmed the tunable selectivity, achieving rare reverse Li+ selectivity in the moderately defective membrane with Li+ flux of 0.64 mol/m(2)& centerdot;h. Further DFT calculations revealed that the diffusion energy barriers for alkali metal ions were significantly influenced by the number and positioning of UiO-66's missing-linker defects. This work highlights the role of defect engineering to tailor angstrom-scale transport pathways in metal-organic framework membranes, providing mechanistic insight for the design of selective monovalent ion separation systems.

Alkali metal batteries (MBs) and anode-free batteries (AFBs) can offer high energy density and simple construction for future electric vehicles. The short lifespan of these batteries is regularly labelled as a significant commercialization barrier, however no clear targets have been defined. In this Snapshot Review, we determine lifespan and other targets for Li- and Na-MBs and AFBs using NMC Li-ion batteries (Li-IBs) as a benchmark. AFBs require lifespans over 1400 cycles to reach Li-IB parity, but currently last only a few hundred cycles. MBs are closer to parity, though large manufacturing challenges remain. Additionally, we assess other requirements including thermal operating ranges, fast charging thresholds, and fabrication demands which must be addressed in MB and AFB research to better match electric vehicle operation. These clear targets will align our efforts to bring these next-generation technologies out of the lab and into mainstream application.

Additive manufacturing (AM) enables spatial control over thermal histories, offering a powerful approach to tailor microstructures and properties within monolithic metallic components. Most work on monolithic architectured materials fabricated with AM has targeted grain-structure attributes such as crystallographic texture, grain size and grain boundaries with limited property gains in mechanical properties such as strength. This study leverages solid-state phase transformation control integrated with programmed, site-specific laser powder bed fusion (LPBF) to fabricate high-performance AISI 1080 plain carbon steel with an architectured microstructure. By tuning local laser energy input, martensitic and bainitic microstructures are selectively formed, resulting in an architectured steel with alternating hard and soft layers. The layered structure achieves a combination of high strength, ductility, and Charpy impact energy superior to uniformly processed counterparts. The improved mechanical response is attributed to the microstructural contrast between the harder and softer regions, which promotes strain partitioning, heterogeneous deformation-induced strengthening, and crack deflection across hard-soft interfaces. This study establishes a manufacturing strategy that links processing control to thermal history and phase selection in a single composition. It also introduces a model that defines the minimum feature size for a stable property contrast in architectured materials. These elements provide transferable guidance to develop advanced architectured materials with enhanced performance and manufacturing versatility.

Recently, zinc trifluoromethanesulfonate (Zn(OTf)2) has been widely used as a key component in zinc-ion battery electrolytes due to its superior performance. However, the early stages of zinc electrodeposition from Zn(OTf)2 remain unexplored by using in situ electrochemical liquid-phase transmission electron microscopy (EC-LPTEM). Here, we directly compare zinc electrodeposition in 0.1 M ZnSO4 and 0.1 M Zn(OTf)2 electrolytes using in situ EC-LPTEM, complemented by ex situ electrochemical tests on symmetric Zn parallel to Zn and V2O5 parallel to Zn full cells. The results reveal distinct electrolyte-dependent differences in early stage nucleation, deposit morphology, and chemical composition. Notably, highly crystalline metallic zinc residues derived from the stripping process are identified in both electrolytes, indicating a common degradation pathway involving irreversible active material loss. This study provides mechanistic insights for designing advanced electrolytes that promote high reversibility, suppress side reactions, and mitigate dendrite formation in zinc-ion batteries.

Periodic oscillations in cell voltage and CO2 reduction reaction product selectivity are commonly observed in laboratory studies using membrane electrode assembly (MEA) CO2 electrolyzers with anion-exchange membranes (AEM). These oscillations hinder both mechanistic studies and progress toward industrial deployment of CO2 electrolyzers. To understand how we might mitigate these oscillations in laboratory-scale experiments, we investigated the effects of three electrolyzer design parameters on system stability: (i) membrane type and thickness, (ii) gas diffusion layer (GDL) properties, and (iii) cell compression, characterized as a normalized thickness difference (NTD) between the GDL and gasket and assembly torque. We found that in our system pairing a higher ionic conductivity AEM with a gas diffusion layer that had cracks in its microporous layer (MPL) in an electrolyser assembled at a medium compression (NTD: 40%, torque: 2 Nm), led to the most stable CO2 to CO electrolysis with pseudo-steady-state CO Faradaic efficiency of around 85% achieved at 100 mA cm−2 for over 50 h. In contrast, lower conductivity AEMs showed earlier and more frequent oscillations related to water flooding, enhanced K+ crossover, and eventual short-circuiting. A lower compression assembly (NTD: 0%, torque: 2 Nm) exhibited a higher initial CO selectivity (>95% for 50 h) but developed more frequent oscillations associated with salt accumulation in the cathode flow channel. Our hypotheses are further supported by tests of an “over-compressed” cell (NTD: 40%, torque: 4 Nm), which exhibited poor water drainage, rapid salt accumulation in the cathode gas channel, and an increased risk of electrode short-circuiting. These observations lead to practical AEM electrolyzer design rules: pairing high-conductive AEMs with crack-rich MPLs and optimizing cell compression to balance membrane-electrode interfacial contact and water drainage to maintain selective and stable CO2 electrolysis.

High-entropy alloys (HEAs) offer a versatile platform for bifunctional electrocatalysis, yet their activity-stability balance under industrial-level current density remains insufficiently understood. Here, we report a self-supported NiFeCoMoW HEA electrode fabricated by pulse electrodeposition on copper foam, forming a binder-free hierarchical architecture with homogeneous elemental distribution. In 1.0 M KOH, NiFeCoMoW@CF delivers strong bifunctional activity, requiring an overpotential of 251 mV to reach 10 mA cm-2 for OER, and enables overall water splitting with a low cell voltage of 1.52 V at 10 mA cm-2 and 1.83 V at 1000 mA cm-2. The electrolyzer operates stably at 1000 mA cm-2 for 100 h with minimal voltage increase. In situ Raman spectroscopy reveals a potential-dependent surface evolution: a persistent Mo/W-O signature is retained across HER and OER, while Ni/Fe/Co reconstruct into an oxyhydroxide-rich surface state under OER, consistent with post-test XPS/HRTEM. This coupled stabilization-reconstruction behavior, enabled by multicomponent coupling and pulse-engineered accessibility, provides mechanistic insight and a practical strategy for durable, noble-metal-free alkaline water electrolysis.

The design of gas diffusion layers (GDL) for fuel cells and electrolysers is increasingly reliant on pore-scale simulations to predict transport properties and liquid management strategies. However, simulation domains are rarely assessed for representativeness beyond porosity measurements, implicitly assuming this geometric convergence ensures representative transport behaviour. Here, property-dependent representative elementary areas (REAs) were assessed for three commercial carbon fibre substrates (CFS) using X-ray micro-computed tomography and pore-scale simulations. Transport REAs consistently exceeded geometric REAs, with porosity-based domains introducing errors over 72% for permeability and 23%for tortuosity. Multiphase simulations only demonstrated REA for two of the three substrates, with clear boundary artifacts on sub-representative domains. This work makes three primary contributions to the literature: (i) identifying low-porosity surface regions, engineered to limit CFS penetration into gas channels, as capillary barriers that trap liquid and cause flooding; (ii) demonstrating a field-of-view limitation of laboratory micro-computed tomography for these materials, where a representative domain cannot always be attained at feasible resolution; and (iii) quantifying the uncertainty introduced by porosity-based REA selection for both single- and multiphase transport. These findings demonstrate that a porosity-based REA is insufficient for reliable pore-scale modelling and motivate property-dependent domain selection when designing porous materials for electrochemical devices.

Electrochemical on-site production of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e(-) ORR) offers environmental benefits, including reduced transport hazards, demand-responsive dosing, and compatibility with renewable energy systems. Although metal-free carbon catalysts are highly promising, a reliable structural descriptor controlling their catalytic selectivity remains unclear. In this work, two series of carbon nanotubes were prepared through controlled thermal reduction and employed to decouple the catalytic contributions from oxygen functional groups and carbon hybridization state. Non-parametric screening methods (mutual information and distance correlation) and uniform quadratic visualizations consistently identify the global carbon hybridization ratio (sp(2)/sp(3)) as the primary determinant of catalytic selectivity & centerdot;H2O2 selectivity follows a volcano-type dependence on sp(2)/sp(3), peaking at approximate to 5.7-6.2. The best catalyst, OCNT-r800 (sp(2)/sp(3) approximate to 5.9), delivers 99.3% selectivity at 0.50 V vs RHE (n = 2.03). Operando Fourier-transform infrared spectroscopy (FTIR) and alkaline flow-cell tests further verify selective H2O2 electrosynthesis at practical current density (similar to 330 mA cm(-2)) with FE >= 95% over 12 h. The results point to a balance between pi-delocalized electronic continuity and adsorption-competent defect environments as a framework-level guideline for designing oxygen-functionalized carbon catalysts for H2O2 production.

This study investigates a pH-universal hydrogen oxidation reaction (HOR) catalyst based on a RuZr alloy supported on zirconium oxynitride, enabling simultaneous optimization of hydrogen and hydroxyl binding energies. The catalyst was synthesized via a urea-glass crystallization route, yielding highly dispersed RuZr alloy nanoparticles strongly coupled with the oxynitride support. RuZr@ZON exhibits high HOR activity with exchange current densities (J0) of 2.14 mA cm- 2 in alkaline, 2.56 mA cm- 2 in acidic and 2.02 mA cm- 2 in neutral media, and achieves a Ru atomic dispersion of 87.9% with an atomic utilization of 5.97%, demonstrating pronounced tolerance to CO poisoning across all pH environments. The enhanced performance originates from a cooperative Volmer-Heyrovsky mechanism facilitated by balanced HBE/OHBE and accelerated H2O desorption, as revealed by electrochemical analysis and DFT calculations. This work establishes a clear structure-activity relationship and provides an effective strategy for designing durable, atom-efficient HOR catalysts operable across a wide pH range.

The development of low-cost, highly efficient catalysts for the oxygen evolution reaction (OER) is one of the key steps for advancing renewable energy production. Increasing the density of high-valence metal species, coupled with rapid surface reconstruction, is a promising, but challenging design strategy for efficient OER catalysts. Herein, we report a facile electronic modulation approach for Ni oxide catalyst design (Ni/CP-TEA-GO), achieved by codecorating the surface with reduced graphene oxide (GO) and an N-group-containing ligand, triethanolamine (TEA), via a simple two-step electrodeposition process. The electrochemically reduced GO serves as an anchor site to couple the Ni sites and induces strong electronic interactions with the Ni sites, improving stability and promoting the formation of high-valence Ni species as active sites. Concurrently, the leaching of TEA further accelerates the generation of high-valence Ni species under the anodic potential. This functional surface modification approach is both cost-effective and scalable, distinguishing it from more complex or noble-metal-based strategies. The Ni/CP-TEA-GO exhibits outstanding OER performance, with a low overpotential of 230 mV at 10 mA·cm-2, rapid OER kinetics with a small Tafel slope of 31 mV·dec-1, and great long-term stability. Moreover, it achieves an overpotential of 360 mV to drive a current density of 50 mV·cm-2 for simulated alkaline seawater oxidation, exhibiting remarkable durability over a 100-h test. This work presents an effective and simple pathway for tailoring the electronic environment to facilitate the accessibility of highly oxidized metal species for the rational design of efficient and cost-effective OER electrocatalysts.

Sodium-ion batteries (SIBs) are a promising technology for advanced energy storage systems. Hard carbon (HC) is a commonly used SIB anode material; however, the Na ion storage mechanism in HC remains poorly understood and highly debated. Here, the paramagnetic species in HC during Na ion storage are systematically studied to elucidate the underlying mechanism at an electronic level using high-resolution electron paramagnetic resonance (EPR) spectroscopy, complemented by in situ Raman spectroscopy, in situ synchrotron X-ray diffraction, and density functional theory calculations. This investigation identifies and characterizes the coexistence of two distinct intercalation processes in HC: Na ion intercalation and Na+-solvent co-intercalation, which are active across both the sloping and plateau voltage regions. Additionally, in the sloping region, Na ions are also stored at in-plane Stone-Wales defect sites, which transition into a quasi-metallic state and subsequently to metallic Na as Na ion intercalation progresses. This transformation is driven by charge redistribution within the graphene layers. These insights establish a direct paramagnetic-electronic structure-electrochemical property relationship in HC, providing new insights into the Na ion storage mechanism. Furthermore, this study highlights the unique capability of EPR spectroscopy in elucidating the charge storage mechanism in electrode materials.

Cathode-electrolyte interphases (CEIs) are crucial for improving battery performance, yet conventional CEIs often show poor adhesion to cathodes, particularly those undergoing pronounced volume fluctuations. Here, we demonstrate the construction of a sulfur-containing CEI (S-CEI) on iron-based Prussian blue analog (FePB) cathodes for sodium-ion batteries via interfacial orbital hybridization between Fe 3d orbitals in FePB and O sp2 orbitals in 1-propene 1,3-sultone (PS). X-ray absorption near edge structure (XANES) spectroscopy combined with density functional theory (DFT) calculations reveals that this 3d-sp2 orbital hybridization redistributes local electron density, altering Fe coordination in FePB and the -SO3- environment in PS. This interaction triggers in situ formation of a uniform S-CEI rich in RSO3Na species on FePB during battery initial cycling. These RSO3Na species strongly coordinate surface Fe centers via the inherited 3d-sp2 coupling, thereby firmly anchoring the S-CEI and stabilizing the FePB lattice. Cryogenic TEM demonstrates that the S-CEI remains chemically and structurally intact after prolonged cycling. In situ synchrotron X-ray diffraction reveals that the FePB@S-CEI exhibits a markedly suppressed cubic-to-tetragonal phase transition, with the unit-cell volume shrinkage rate reduced from 18.5 to 5.7%/V. Consequently, the FePB@S-CEI achieves stable cycling with only 0.013% capacity loss per cycle over 1500 cycles at 1C, high rate capability up to 90C, and reliable performance across -20 to 60 °C. This study presents a general strategy for designing robust CEIs through interfacial orbital hybridization to enhance battery performance.

Carbon molecular sieve membranes (CMSM) have been extensively researched for industrial gas separation owing to their high permeance, tailored selectivity, and stability in corrosive and high-temperature environments. In recent years, CMSM development has focused on modifying the structure of carbon precursors to improve permeability. In this study, we designed a new thin film CMSM incorporating cobalt-2,6-bis(2benzimidazolyl) pyridine (CoB) dopant within the polyetherimide (PEI) precursor on tubular alpha-alumina substrates. CoB-doped CMSM (CoB_CM) with systematic CoB concentrations (0-10 w/w %) were investigated to understand the co-pyrolysis effect of CoB on the PEI-derived CMSM microstructure and gas transport (single gas permeation and binary gas separation) over the course of 10 days, with an average membrane thickness of 10 mu m. These were fabricated using a vacuum-assisted, dip-coating process followed by vacuum pyrolysis at 600 degrees C. The binary gas separation (H2/CH4, 50/50 vol%) tests further demonstrate the enhanced stability and separation performance of the 1CoB_CM membrane over the PEI_CM membrane, producing H2 permeability of 2800 Barrer (282.2 +/- 0.35 GPU) and H2/CH4 selectivity of 234 +/- 2. These results suggest that CoB can effectively tune the micropore architecture of the CMSM, particularly further enhancing ultramicroporosity and gas transport of smaller gases, thereby offers a promising strategy of developing high-performance carbon molecular sieving membranes for challenging gas separations.

A universal design framework for high‐performance catalysts remains challenging due to diverse structures and active sites. We developed a framework integrating weighted atom‐centered symmetry function (wACSF) descriptors with machine learning, microkinetic modeling, and high‐throughput screening. The wACSF descriptors unify geometric and chemical characteristics of active sites across different catalyst families. ML models trained on wACSF accurately predicted adsorption free energies of hydroxyl (ΔG OH * , R 2 = 0.84) and oxygen (ΔG O* , R 2 = 0.91) for intermetallic alloys, metal oxides, perovskites, and single‐atom catalysts in the two‐electron water oxidation reaction (2e − WOR). Density functional theory and microkinetic modeling yielded a universal 2e − WOR volcano model that agreed well with experiments. High‐throughput screening with ML‐predicted ΔG OH* identified LiScO 2 , which achieved 90% H 2 O 2 Faradaic efficiency at 2.2 V vs. reversible hydrogen electrode (RHE) with 168‐hour stability (82%–86% retention). Experimental activity (log( j ) = 1.56) matched theoretical predictions (log( j ) = 1.28) within 5% deviation at 2.4 V_RHE. This universal framework provides a general paradigm for rational catalyst design and is implemented in the Digital Catalysis Platform ( DigCat ), enabling efficient discovery across diverse material classes and electrochemical reactions.

Natural biopolymers have attracted extensive research interest in the past decades for application in flexible energy conversion and storage devices, which has been largely motivated by the rapid development of Internet-of-Things (IoT) devices and the increasing demand for portable power sources to enable autonomous functionality. Various natural biopolymers, such as cellulose, chitin/chitosan, starch, silk, gelatin, agarose, and lignin, have been explored to date. Natural biopolymers have several prominent advantages over synthetic polymers, including low cost, high abundancy, excellent recyclability, mechanical flexibility, biodegradability and biocompatibility. Natural biopolymers, being used alone or in combination with synthetic polymers, have attracted increasing research attention for various functional components in flexible energy devices, including lightweight and flexible substrates, electrode materials, templates for designing hierarchical structures, and host polymers/gelling agents for electrolytes. In particular, natural biopolymers have been demonstrated as promising candidates for high-performance gel electrolytes with decent ionic conductivity, high flexibility, and electrochemical stability. This chapter presents the progress in natural biopolymer-based flexible energy conversion and storage devices, such as solar cells, thermoelectric devices, supercapacitors, and batteries. The key challenges and future perspectives are also discussed by the end of the chapter to shed light on the future research and development.

The world's transition from a fossil-fuel-driven society to a future net-zero or negative carbon dioxide emission society will require a significant scale-up of Power-to-X technologies to capture and convert CO2 to low carbon intensity fuels and chemicals. The deployment of Power-to-X technologies at gigawatt scales necessary to impact CO2 emissions and replace existing fossil-fuel-dependent processes will require vast quantities of raw materials and minerals. Many of the materials required in Power-to-X systems, such as rare earth metal yttrium and iridium, differ from those used to construct and operate petroleum-hydrocarbon-based processes for the last 100 years. Thus, electrolyzer manufacturers and mineral producers face significant challenges in matching supply to the growing demand. In this Perspective, we identify critical materials needed for Power-to-X electrolyzers and analyze the impacts and risks of these materials' existing global supply chains. We then provide an overview of methodologies for Environmental Life Cycle Assessment (LCA) and Social Life Cycle Assessment (SLCA) that we encourage scientific communities to adopt early in the research process to evaluate the multidimensional socio-environmental impacts throughout a product's life cycle, from raw material extraction and processing to manufacturing, use, and end-of-life disposal. We advocate that life cycle thinking is crucial for the informed, just and ethical development of disruptive technologies and systems such as Power-to-X technologies.

As the most typical high-strength stainless steel, the heat-treated AISI 440C steel has low machinability. It is also not weldable due to the high carbon content. Additive manufacturing, specifically laser powder bed fusion (LPBF), offers a promising solution for fabricating near-net shape components with this alloy. To address the limited research on the LPBF of AISI 440C steel, this work investigates the LPBF processability, microstructure and phase evolution of the AISI 440C steel, focussing on the role of post-processing treatments on improving mechanical properties, wear and corrosion resistance compared to its wrought counterpart. Our results indicate that highly dense AISI 440C components with > 99.98

Solid polymer electrolytes（SPEs） with high ionic conductivity are desirable for solid-state lithium metal batteries（SSLMBs） to achieve enhanced safety and energy density.Incorporating nanofillers into a polymeric matrix to develop nanocomposite solid electrolytes（NCSEs） has become a promising method for improving the ionic conductivity of the SPEs.Here,a novel ZIF-8-functionalized NCSE was prepared for high-temperature S SLMB s using an in situ radical polymerization method.It is found that the ZIF-8 nanoparticles could reduce the crystallinity of polymer segments and offer a Lewis acid surface that promotes the dissociation of lithium bis（trifluoromethanesulfonyl）imide（LiTFSI） and stabilizes the TFSI - anion movement.Thus,the as-prepared NCSE exhibits an outstanding ionic conductivity of 1.63 × 10 -3 S·cm -1 ,an electrochem ical stability window of 5.0 V at 80℃,and excellent interface compatibility with lithium metal anode with a stable polarization over 2000 h.Furthermore,the assembled SSLMBs with LiFePO 4 cathode show dendrite-free Li-metal surface,good rate capability,and stable cycling stability with a capacity retention of 70% over 1000 cycles at a high temperature of 80 ℃.This work provides valuable insights into promoting the ionic conductivity of SPEs.