Abstract Hydroxide-induced degradation and swelling of organic anion exchange membranes (AEMs) fundamentally limit the advancement and industrialization of alkaline hydrogen production. Here, we present a free-standing inorganic AEM comprising 90 wt % layered double hydroxides within a three-dimensionally fibrillated polytetrafluoroethylene scaffold. The membrane achieves zero swelling, suppressed hydrogen crossover, and a low area-specific resistance of 0.089 Ω cm2 while remaining stable for 1344 h in 1 M and 30 wt % KOH at 80 °C, under which commercial polymeric membranes fail rapidly. The confined hydrogen-bond network within layer double hydroxide galleries promotes Grotthuss-dominated OH– transport as supported by ab initio molecular dynamics. The membrane sustains 1 A cm–2 operation for 550 h in AEM water electrolyzers and 425 h in alkaline water electrolyzers, establishing a durable inorganic AEM platform for alkaline hydrogen production and related electrochemical energy technologies.
Abstract Sustainable Na-ion batteries (NIBs) have attracted widespread attention in transportation vehicles and large-scale energy storage systems due to abundant sodium sources, high safety records, and favorable all-climate performance. However, their overall performance and cost are largely governed by cathode materials, which determine practical application and commercial market prospects. Iron- and/or manganese-based polyanionic cathodes not only reduce cost but also provide high working voltage and desirable cycling stability, benefiting from strong inductive effects and robust structural covalency of polyanionic groups, making them attractive for sustainable batteries. This review summarizes material design concepts, research progress, technological bottlenecks, and development directions for various types of phosphate, pyrophosphate, and sulfate cathodes. Besides, we focus on clarifying the structure–function relationships by comprehensively comparing synthesis methods, crystal structures, electrochemical behavior, and reaction mechanisms of Fe/Mn-based polyanionic cathodes for NIBs. This review provides critical guidance for the future advancement of practical NIBs.
Abstract Sn–Pb perovskites are promising low-bandgap absorbers for photovoltaics, but their efficiency is limited by the low open-circuit voltage, VOC. The VOC deficit, WOC, is related to energetic disorder, characterized by the Urbach energy, EU, comprising static and dynamic contributions. For Cs0.25FA0.75SnxPb1–xI3, these contributions were determined using time-resolved microwave conductivity (TRMC) and photoluminescence (PL) measurements between 180–350 K. For Pb-based films, both techniques provided similar EU values. However, for Sn-containing compositions (x = 0.2 and 0.5), TRMC-derived EU were twice higher than those found by PL. These differences arise from compositional heterogeneity: TRMC integrates absorption over the entire thickness while the PL-derived absorption originates from low-bandgap domains, likely from the Sn-rich top surface as revealed by X-ray photoelectron spectroscopy (XPS). The PL-derived EU trend corresponds to the bandgap-normalized WOC, which is smallest for x = 0.5 (∼9.2 meV), attributed to the low dynamic contribution originating from the lower mass of Sn.
Abstract Organic electrodes for secondary batteries are hindered by molecular dissolution and low operating voltages. Herein, we report a coordination-driven strategy to construct insoluble π–d conjugated small molecules (BTD-M, M = Cu, Ni, or Zn) featuring high-voltage p-type triphenylamine-derived ligands (N4′,N4′-diphenyl-[1,1′-biphenyl]-3,4,4′-triamine, BTD). By precisely tuning metal–ligand coordination, we thermodynamically lock discrete molecules against electrolyte dissolution while preserving unhindered access to active sites. The optimal BTD-Cu exhibits a narrow bandgap of 0.7 eV, enabling extensive electron delocalization for electronic conductivity. This electrode delivers a near-theoretical capacity of 134 mAh g–1 at 1C and still delivers 83 mAh g–1 at 10C. Leveraging bipolar redox chemistry of p-type ligands and metal centers, the symmetric all-organic dual-ion battery achieves an average voltage of 2.4 V and a cycle life exceeding 1000 cycles. This work establishes insoluble π–d conjugated small molecules as an accessible platform for organic battery design.
Abstract Ceria-based thermochemical cycles offer a promising route to solar hydrogen, but require reduction above 1400 °C and large temperature swings. Here, building on electrically assisted CeO2 reduction, we demonstrate repeated isothermal CeO2-based water-splitting cycles at 700–900 °C and 0.5–2.0 V. Porous CeO2−YSZ bilayer pellets with different composition ratios undergo electrically assisted reduction and steam re-oxidation at the same temperature, producing O2 and H2 in separate steps without thermal cycling. The process reaches H2/O2 ratios up to 1.9, reproducible H2 productivity over 10 cycles, and H2 yields up to 49 ± 2 μmol gCeO2−1 cycle−1 after only 20 min of electrically assisted reduction. Extended-reduction experiments show that the best composition remains only ∼0.10 V below the applied bias on an equivalent thermodynamic-voltage basis. Reactor-scale projections based on gas utilization in an existing ceria reactor give a solar-to-H2 efficiency of 5.6% without assuming improvements to the CeO2−YSZ architecture.
