Haeseong Jang

Direct electrolysis of seawater for hydrogen production offers a vital route to circumvent freshwater limitations and advance a sustainable hydrogen economy. Herein, we present a novel catalyst design strategy based on the co-doping of Ru atoms with strong chloride affinity and Cr atoms serving as Lewis acid centers into a nickel phosphide matrix (RuCr-Ni ₃ P). This material is a highly active anode for direct alkaline seawater electrolysis, offering outstanding oxygen evolution reaction (OER) selectivity and operational longevity exceeding 4000 h under industrially relevant conditions. Mechanistic investigations reveal that chloride ions are not merely detrimental impurities, but are selectively captured by Ru sites to form a dynamic Ru–Cl coordination motif. This interaction electronically modulates adjacent Ni active centers, facilitating the generation of high-valent Ni ^>3+ species and switching the dominant OER pathway from the lattice oxygen mechanism (LOM) to the more efficient adsorbate evolution mechanism (AEM). Simultaneously, Cr sites promote the formation of Cr–OH species, which cooperatively create a localized alkaline microenvironment favorable for OER on the high-valent Ni centers. This dual-site synergistic mechanism, wherein Ru sites regulate chloride and Ni/Cr sites drive catalysis, effectively transforms Cl ⁻ from a performance-limiting species into a chemical switch that concurrently enhances both activity and stability.

Manganese dioxide (MnO2) is a promising cathode material for aqueous zinc-ion batteries (AZIBs) owing to its low cost and high theoretical capacity. However, its practical application is hindered by sluggish reaction kinetics and structural instability arising from Mn dissolution and irreversible phase transitions during repeated cycling. In this study, an amorphous–crystalline MnO2 (AMC-MnO2) heterostructure is constructed to address these limitations, in which amorphous MnO2 (AM-MnO2) provides abundant active sites and structural flexibility, while crystalline MnO2 (C-MnO2) offers continuous ion diffusion pathways and structural robustness. The heterointerface promotes interfacial charge redistribution, thereby improving the charge-transfer kinetics and structural stability through a buffering effect. Electrochemical analyses revealed that AMC-MnO2 exhibited faster H+ diffusion kinetics than AM-MnO2 and C-MnO2 while maintaining comparable Zn2+ diffusion behavior. Consequently, the AMC-MnO2 electrode delivered enhanced rate capability and superior cycling stability compared with AM-MnO2 and C-MnO2. These findings demonstrate that amorphous–crystalline heterostructure engineering effectively regulates Zn2+/H+ storage behavior and provides a rational strategy for developing high-performance MnO2 cathodes for aqueous zinc-ion batteries.

Uncontrolled dendrite growth and unstable solid electrolyte interphase (SEI) formation hinder the commercialization of high-energy-density lithium metal batteries. This work presents a heterostructured interfacial engineering strategy to address these challenges. A multifunctional artificial SEI is constructed on a carbon fiber (CF) host by infusing molten Li into a predesigned SnF2@SnO2@CF framework. SnF2 and SnO2 spontaneously react with Li to form a unique hierarchical heterostructure consisting of a mechanically robust, LiF-rich outer layer that suppresses dendrite growth and an ionically conductive, Li2O-rich inner layer that enhances Li+ transport. The LiF–Li2O grain boundaries further facilitate exceptionally fast Li+ diffusion. This artificial SEI integrates with a lithiophilic Li22Sn5 alloy backbone, which provides uniform nucleation sites for Li deposition. Benefiting from these synergistic features, the Li@SnF2@SnO2@CF electrode exhibits outstanding electrochemical performance. Symmetric cells demonstrate high-rate capability, maintaining an overpotential below 0.05 V at 50 mA/cm2 and stable cycling for more than 2000 h. When paired with a high-voltage NCM811 cathode, the full cell delivers excellent rate performance and long-term stability. This study provides a practical and effective pathway for advancing next-generation high-energy-density LMBs.

Achieving high‐performance single‐atom catalysts (SACs) for rechargeable Zn–air batteries (ZABs) requires simultaneous optimization of pore structure and coordination environment. However, MOF‐derived SACs typically feature micropore‐dominated carbon frameworks and planar coordination symmetry, restricting oxygen diffusion and intrinsic activity. Here, we introduce a dual‐engineering strategy that combines polymer encapsulation with wavy graphene oxide (GO) substrates. Bimetallic Co/Zn zeolitic imidazole framework (Co‐ZIF‐8) precursors were coated with polyvinylpyrrolidone (PVP) and assembled on GO, followed by pyrolysis to yield CoSA@P‐NC/rGO. The PVP layer induced mesopores via controlled shrinkage of the ZIF structure, while the wavy GO substrate modulated the coordination environment of atomically dispersed Co─N _x sites, extending bond lengths and introducing symmetry distortion. Benefiting from these structural and electronic features, CoSA@P‐NC/rGO exhibited outstanding bifunctional activity, with a half‐wave potential of 0.90 V for oxygen reduction reaction and a low overpotential of 397 mV at 10 mA cm ⁻² for oxygen evolution reaction. When employed as a ZAB cathode, it achieved a high power density of 190 mW cm ⁻² , a specific capacity of 832 mA h g ⁻¹ , and durable cycling over 600 cycles. This synergistic strategy of pore and coordination engineering provides a promising platform for developing efficient, long‐lived SACs for energy storage applications.

The single-atom Zn and lattice S stably immobilize SO ₄ ²⁻ groups on RuO _{2– x} , simultaneously modulating reaction pathways, breaking scaling limitations, which enable unprecedented activity and durability for the acidic OER.