Wei Wen

Rechargeable seawater battery (RSWB) is a promising candidate for low‐cost energy storage while solar seawater desalination (SSD) can produce clean water from seawater, yet no attempts have been made to integrate them, preferably with a mutual enhancement effect. In this study, we report an ε‐MnO ₂ material with bifunctions of ion storage for RSWB and photothermal effect for SSD. The integration of RSWB and SSD leads to a mutual enhancement effect, in sharp contrast to traditional integrations. The ε‐MnO ₂ displays a high specific capacity of 265 mAh g ⁻¹ for RSWB. When coupled with SSD, the specific capacity obviously increases, and meanwhile the seawater evaporation rate also increases substantially during the charge/discharge process. The mutual enhancement effect is attributed to the temperature increase in cathode caused by the photothermal effect of ε‐MnO ₂ and the weakened hydrogen‐bonding interaction arising from the charge/discharge process. This work would provide new perspectives on energy storage and clean water production.

Rechargeable seawater batteries are emerging as sustainable electrochemical energy‐storage systems that directly exploit natural seawater as an abundant electrolyte and ion reservoir. Beyond conventional seawater‐activated primary batteries and half‐seawater rechargeable systems, fourth‐generation seawater batteries represent a distinct concept in which both electrodes operate directly in natural seawater without nonaqueous anolytes or NASICON‐type ceramic separators. This review clarifies the conceptual boundary between seawater‐based batteries, where seawater mainly serves as a solvent, catholyte, or supporting medium, and genuine rechargeable seawater batteries, where intrinsic seawater ions participate in charge storage and charge compensation. We discuss the fundamental electrochemistry of seawater electrolytes, including ion transport, oxygen/chlorine side reactions, and seawater–electrode interfacial chemistry. Recent advances in cathode materials, including cation‐intercalation hosts and oxygen electrocatalysts, are summarized together with emerging anode materials for single‐ion storage and multi‐ion costorage. Key challenges involving chloride‐induced corrosion, competitive ion storage, interfacial instability, and marine deployment are critically assessed. Future directions are proposed to guide the development of efficient, durable, and scalable rechargeable seawater batteries for marine energy storage.

Oxygen vacancy modulations are effective to tailor transition metal oxides for applications in high performance electrochemical energy storages; yet a simple, one-step modulation tactic is scarce. In this work, MnCo2O4 with abundant oxygen vacancies is anchored on carbon cloth (MCO-NaCl) through a molten salt synthesis in which NaCl serves as the vacancy mediator. Extra formation of oxygen vacancy is observed in the surface region due to the doping of chloride-ions. A positive correlation is confirmed between the content of oxygen vacancies and the amount of chloride-ions. The optimized MCO-NaCl-0.5 electrode with 17.28% oxygen vacancy exhibits a much enhanced performance of 8.17 F cm-2 (2368.1 F g-1) at 5 mA cm-2 and possesses a good capacitance retention of 90.1% after 8000 charge-discharge cycles. An asymmetric supercapacitor is assembled using the MCO-NaCl-0.5 as the positive electrode and TiO2 nanowires precipitated on activated carbon cloth (TiO2@ACC) as the negative electrode. The device delivers a desirable energy density of 63.96 Wh kg-1 at a power density of 955.5 W kg-1 and retains 33.92 Wh kg-1 at a high power output of 10482.3 W kg-1, together with an outstanding stability of 98.4% retention after 10000 cycles. The doping chloride-ion-mediated oxygen vacancy tactic developed herein provides an efficient pathway for the modification of metal oxide electrodes demonstrating great promise for energy storage applications.

Rechargeable aqueous zinc‐ion batteries have garnered considerable attention due to their intrinsic safety, high theoretical capacity, and low cost. However, problems such as zinc dendrite growth, hydrogen evolution reaction, and severe corrosion hinder their practical deployment. Herein, we fabricate a homogeneous high‐entropy oxide powder (Co _0.2 Cu _0.2 Mg _0.2 Ni _0.2 Zn _0.2 )O with a single‐phase rock‐salt structure, as a protective artificial interphase for the Zn anode. The multicomponent oxide layer enables selective Zn ²⁺ adsorption and enhanced ion migration uniformity. Furthermore, its intrinsic hydrophobicity and strong desolvation ability suppress parasitic side reactions, thereby facilitating uniform and reversible Zn plating/stripping. As a result, the modified Zn anode exhibits an ultralong cycling lifespan of 1800 h at 10 mA cm ⁻² in a 2 M ZnSO ₄ electrolyte, and retains 750 h of stable cycling even in a natural seawater‐based ZnSO ₄ system at 20 mA cm ⁻² . This approach is further validated with a compositional variation—(Co _0.2 Cu _0.2 Mn _0.2 Ni _0.2 Zn _0.2 )O—demonstrating robust cycling over 1300 h at 10 mA cm ⁻² . Furthermore, full cells assembled with an I ₂ cathode show enhanced electrochemical performance. These findings highlight the dual roles of high‐entropy materials in simultaneously accelerating the kinetics of Zn ²⁺ transport and homogenizing zinc deposition, offering a promising strategy for the stabilization of zinc metal anodes in aqueous batteries.

Aqueous Ni─Zn batteries are highly attractive for grid‐scale energy storage due to their safety, low cost, and environmental friendliness. However, their energy density is limited by the underutilization of nickel‐based cathode materials. Here, a bond‐discretization strategy in NiO is developed to overcome this challenge. By designing a low‐symmetry crystallographic structure with a reduced Ni–Ni coordination number of 9, the NiO cathode achieves a near‐theoretical capacity for the one‐electron reaction. This structural modification leads to a discretization of Ni─O bonds and achieves a ratio of 50% for weak O─H bonds in the transformation product of Ni(OH) ₂ , equal to the proportion (50%) of H atoms that needs to be detached from Ni(OH) ₂ to NiOOH, which can realize nearly theoretical capacity for the one‐electron reaction. The bond‐discretization also promotes catalytic activity for oxygen evolution and oxygen reduction reactions, enabling the integration of Ni─Zn batteries with Zn‐air batteries. The low‐symmetry NiO cathode demonstrates high specific capacity, excellent rate capability, and superior cycling stability, with a full cell paired with a zinc anode achieving a specific energy of 459 Wh kg ⁻¹ at a specific power of 995.7 W kg ⁻¹ . This work provides a new bonding‐engineering strategy for constructing high‐performance energy storage devices.

Molten salt aluminum batteries (MSABs) hold significant promise for grid-scale energy storage due to the low cost and high capacity of the aluminum anode. However, an aluminum dendrite stemming from nonuniform electrodeposition leads to safety and stability issues. Here, we describe a membrane electrode with predeposited aluminum metal featuring surface-mediated nucleation and growth behavior for operation in alkali chloroaluminate melt electrolytes. The introduction of TiN, as aluminophilic sites, facilitates the initial growth of aluminum on TiN by forming Al-N bonding, thereby enabling uniform aluminum nucleation and mediated growth along the TiN/C fiber, resulting in reversible and dendrite-free aluminum plating/stripping. The TiN/C@Al electrode enables symmetric cells to maintain stable cycling for over 850 h (10.0 mA cm^-2; 5.0 mA h cm^-2) and shows high rate performance at up to 30.0 mA cm^-2. The Al-graphite cell using a TiN/C@Al anode demonstrates long-term stability over 7000 cycles at 2.0 A g^-1 and enhanced rate capability with 72.2 mA h g^-1 even at 5.0 A g^-1. To validate practical scalability, we designed an Ah-level TiN/C@Al-based molten salt Al-graphite pouch cell. This approach offers a scalable pathway for overcoming the limitations of state-of-the-art anodes in MSABs, enabling high-performance and cost-effective energy storage solutions.

The acidic oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane electrolyzer (PEMWE) often face a trade‐off between activity and stability due to inherent linear relationship and overoxidation of metal atoms in highly oxidative environments, while following the conventional adsorbate evolution mechanism (AEM). Herein, a favorable AEM‐derived proton acceptor‐electron donor mechanism (PAEDM) is proposed in RuO ₂ by constructing interstitial‐substitutional mixed solid solution structure (denoted as C,Ta‐RuO ₂ ), which can effectively break the activity‐stability trade‐off of RuO ₂ in acidic OER. In situ spectroscopy experiments and theoretical calculations reveal that the interstitial C as the proton acceptor reduces the deprotonation energy barrier, enhancing catalytic activity, while the substitutional Ta as the electron donor donates electrons to the Ru sites via bridging oxygen, weakening the Ru─O bond covalency and preventing over‐oxidation of surface Ru, thereby ensuring long‐term stability. Under the guidance of this mechanism, the optimized C,Ta‐RuO ₂ simultaneously achieves far low overpotential (η ₁₀ = 171 mV) and ultra‐long stability (over 1300 h) for the acidic OER. More remarkably, a homemade PEMWE using C,Ta‐RuO ₂ as the anode also shows high water splitting performance (1.63 V@1 A cm ⁻² ). This work supplies a novel strategy to guide future developments on efficient OER electrocatalysts toward water oxidation.

Three-dimensional TiO₂ hierarchical nanowire arrays were synthesized featuring nanocavities via a hydrogen peroxide-assisted wet chemical reaction, followed by a simple liquid-phase deposition process. We subsequently decorated the TiO₂ arrays with dopamine, leveraging its enediol ligand for chelation. Reduced nicotinamide adenine dinucleotide (NADH), a cofactor for over 300 dehydrogenases, serves as the targeted analyte to assess the PEC sensing performance of the sensor. The developed sensor exhibited a linear concentration range for NADH detection of 0.05 to 50 µM, achieving a high sensitivity of 0.29 μA∙μM^-1∙cm^-2 and a low detection limit of 0.03 μM (signal-to-noise ratio of 3). Notably, PEC performance of the resulting sensor surpassed that of commercial TiO₂ (P25)-based sensors. The enhanced sensing capabilities can be attributed to several factors: the TiO₂ hierarchical nanowire arrays with nanocavities provide a larger surface area, abundant active sites, and shorter molecular diffusion lengths for surface adsorption and reaction, thereby reducing response times and improving sensitivity. Additionally, the coupling of TiO₂ with dopamine enhances visible light absorption and optimizes charge transfer dynamics. These findings open a new avenue for designing high-performance three-dimensional nanoarchitectures for PEC sensing applications.

Developing highly active and CO‐resistant Ru‐based catalysts for the alkaline hydrogen oxidation reaction (HOR) can advance the large‐scale application of alkaline hydrogen fuel cells but remains a huge challenge. Herein, a pure phase W₂C supported Ru cluster catalyst (Ru/W₂C) is successfully synthesized through a one‐step carburization method. It is found that the charge transfer from W₂C to the strongly anchored Ru clusters forms the electron‐rich Ru^δ− sites and electron‐deficient W^δ+ sites, which significantly weakens the adsorption strength of ^*H and ^*CO, strengthens the binding of ^*OH and improves the water connectivity in the electric double layer. The Ru/W₂C catalyst shows superior mass activity (2163 mA mg_PGM⁻¹) in alkaline HOR, which is 12.52 and 20.62 times higher than that for Pt/C and Ru/C, respectively. Owing to the weak adsorption and fast removal rate of CO, the Ru/W₂C exhibits outstanding CO tolerance, with 88% of the initial activity being retained in the durability test, whereas the Ru/C and Pt/C suffer from severe deactivation. These findings may guide the design of advanced alkaline HOR catalysts based on the pure phase tungsten carbide.