Explore the vast range of titles available.

Iron-chromium flow batteries (ICRFBs) have emerged as an ideal large-scale energy storage device with broad application prospects in recent years. Enhancement of the Cr3+/Cr2+ redox reaction activity and inhibition of the hydrogen evolution side reaction (HER) are essential for the development of ICRFBs and require a novel catalyst design. However, elucidating the underlying mechanisms for modulating catalyst behaviors remains an unresolved challenge. Here, we show a novel precisely controlled preparation of a novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles. The density functional theory analysis reveals the In catalyst has a significant adsorption effect on the reactants and improves the redox reaction activity of Cr3+/Cr2+. Moreover, H+ is more easily absorbed on the surface of the catalyst with a high migration energy barrier, thereby inhibiting the occurrence of HER. The assembled ICRFBs have an average energy efficiency of 83.91% at 140 mA cm−2, and this method minimizes the electrodeposition process and cleans the last obstacle for industry long cycle operation requirements. The ICRFBs exhibit exceptional long-term stability with an energy efficiency decay rate of 0.011% per cycle at 1000 cycles, the lowest ICRFBs reported so far. Therefore, this study provides a promising strategy for developing ICRFBs with low costs and long cycle life. Schematic diagram of the ICRFBs and the fabrication of the electrode. [Display omitted] •A novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles.•DFT simulation explains the mechanism of In catalysts to enhance Cr3+/Cr2+ reaction activity and inhibit HER.•We successfully demonstrated the scale-up from laboratory-level experiments to a kW-scale stack.

A key challenge to realizing practical electrochemical N 2 reduction reaction (NRR) is the decrease in the NRR activity before reaching the mass-transfer limit as overpotential increases. While the hydrogen evolution reaction (HER) has been suggested to be responsible for this phenomenon, the mechanistic origin has not been clearly explained. Herein, we investigate the potential-dependent competition between NRR and HER using the constant electrode potential model and microkinetic modeling. We find that the H coverage and N 2 coverage crossover leads to the premature decrease of NRR activity. The coverage crossover originates from the larger charge transfer in H + adsorption than N 2 adsorption. The larger charge transfer in H + adsorption, which potentially leads to the coverage crossover, is a general phenomenon seen in various heterogeneous catalysts, posing a fundamental challenge to realize practical electrochemical NRR. We suggest several strategies to overcome the challenge based on the present understandings. Practical electrochemical N 2 reduction reaction is challenged by competing side reactions. Here a combination of DFT and mikrokinetic modelling reveals the potential-dependent competition between electrochemical ammonia production and hydrogen evolution on a single-site iron catalyst embedded in N-doped graphene.

Zinc-ion batteries have demonstrated promising potential for future energy storage, whereas drawbacks, including dendrite growth, hydrogen evolution reaction, and localized deposition, heavily hinder their development for practical applications. Herein, unlike elaborated structural design and electrolyte excogitation, we introduce an effective parts-per-million (ppm)-scale electrolyte additive, phosphonoglycolic acid (PPGA), to overcome the intrinsic issues of zinc negative electrode in mild acidic aqueous electrolytes. Profiting from absorbed PPGA on zinc surface and its beneficial interaction with hydrogen bonds of adjacent water molecules, stable symmetric stripping/plating of zinc in aqueous ZnSO 4 electrolyte at around 25  o C was achieved, procuring 362 and 350 days of operation at 1 mA cm -2 , 1 mAh cm -2 and 10 mA cm -2 , 1 mAh cm -2 , respectively. As a proof-of-concept, an Ah-level Zn||Zn 0.25 V 2 O 5 ·nH 2 O pouch cell examined the validity of PPGA and sustained 250 cycles at 0.2 A g -1 and around 25 o C without capacity loss. The Zn||Br 2 redox flow battery demonstrated an operation of over 800 h at 40 mA cm -2 , 20 mAh cm -2 with an average coulombic efficiency of 98%, which is attributed to restrained dendrite growth and side effects. This work is believed to open up new ways forward for knowledge of electrolyte additive engineering. Challenges of zinc electrodes imped their progress in energy storage. Here, authors propose a parts-per-million scale electrolyte additive, phosphonoglycolic acid, enabling Zn stripping/stripping for nearly a year in coin cells, and exhibiting high durability in pouch cells and redox flow batteries.

Hydrogen produced from neutral seawater electrolysis faces many challenges including high energy consumption, the corrosion/side reactions caused by Cl - , and the blockage of active sites by Ca 2+ /Mg 2+ precipitates. Herein, we design a pH-asymmetric electrolyzer with a Na + exchange membrane for direct seawater electrolysis, which can simultaneously prevent Cl - corrosion and Ca 2+ /Mg 2+ precipitation and harvest the chemical potentials between the different electrolytes to reduce the required voltage. In-situ Raman spectroscopy and density functional theory calculations reveal that water dissociation can be promoted with a catalyst based on atomically dispersed Pt anchored to Ni-Fe-P nanowires with a reduced energy barrier (by 0.26 eV), thus accelerating the hydrogen evolution kinetics in seawater. Consequently, the asymmetric electrolyzer exhibits current densities of 10 mA cm −2 and 100 mA cm −2 at voltages of 1.31 V and 1.46 V, respectively. It can also reach 400 mA cm −2 at a low voltage of 1.66 V at 80 °C, corresponding to the electricity cost of US$1.36 per kg of H 2 ($0.031/kW h for the electricity bill), lower than the United States Department of Energy 2025 target (US$1.4 per kg of H 2 ). Hydrogen produced directly from neutral seawater is promising but challenging due to seawater’s complex composition. Here, the authors report a Na + -conducted pH-asymmetric electrolyzer that can directly split seawater into hydrogen with low electricity cost and nearly zero chloride interference.

Alkaline hydrogen evolution reaction (HER) for scalable hydrogen production largely hinges on addressing the sluggish bubble‐involved kinetics on the traditional Ni‐based electrode, especially for ampere‐level current densities and beyond. Herein, 3D‐printed Ni‐based sulfide (3DPNS) electrodes with varying scaffolds are designed and fabricated. In situ observations at microscopic levels demonstrate that the bubble escape velocity increases with the number of hole sides (HS) in the scaffolds. Subsequently, we conduct multiphysics field simulations to illustrate that as the hole shapes transition from square, pentagon, and hexagon to circle, where a noticeable reduction in the bubble‐attached HS length and the pressure balance time around the bubbles results in a decrease in bubble size and an acceleration in the rate of bubble escape. Ultimately, the 3DPNS electrode with circular hole configurations exhibits the most favorable HER performance with an overpotential of 297 mV at the current density of up to 1000 mA cm−2 for 120 h. The present study highlights a scalable and effective electrode scaffold design that promotes low‐cost and low‐energy green hydrogen production through the ampere‐level alkaline HER. Three‐dimensional‐printed Ni‐based sulfide (3DPNS) electrodes with different scaffolds are designed and manufactured, aiming at elucidating the relationship between the number of hole sides (HS) within the electrode scaffold and bubble escape. Notably, the 3DPNS‐circle electrode, with the highest number of HS, demonstrates exceptional activity in the ampere‐level alkaline hydrogen evolution reaction (HER).

Aqueous zinc-ion batteries, in terms of integration with high safety, environmental benignity, and low cost, have attracted much attention for powering electronic devices and storage systems. However, the interface instability issues at the Zn anode caused by detrimental side reactions such as dendrite growth, hydrogen evolution, and metal corrosion at the solid (anode)/liquid (electrolyte) interface impede their practical applications in the fields requiring long-term performance persistence. Despite the rapid progress in suppressing the side reactions at the materials interface, the mechanism of ion storage and dendrite formation in practical aqueous zinc-ion batteries with dual-cation aqueous electrolytes is still unclear. Herein, we design an interface material consisting of forest-like three-dimensional zinc-copper alloy with engineered surfaces to explore the Zn plating/stripping mode in dual-cation electrolytes. The three-dimensional nanostructured surface of zinc-copper alloy is demonstrated to be in favor of effectively regulating the reaction kinetics of Zn plating/stripping processes. The developed interface materials suppress the dendrite growth on the anode surface towards high-performance persistent aqueous zinc-ion batteries in the aqueous electrolytes containing single and dual cations. This work remarkably enhances the fundamental understanding of dual-cation intercalation chemistry in aqueous electrochemical systems and provides a guide for exploring high-performance aqueous zinc-ion batteries and beyond. The dual-cations electrochemical system was considered to be a promising strategy to facilitate sluggish diffusion kinetics. Here the authors prepare zinc-based alloy anode with three-dimensional interface, thus to improve the interfacial stability, achieve high-performing battery system in the aqueous electrolytes containing dual cations.

The dendrite growth of zinc and the side reactions including hydrogen evolution often degrade performances of zinc-based batteries. These issues are closely related to the desolvation process of hydrated zinc ions. Here we show that the efficient regulation on the solvation structure and chemical properties of hydrated zinc ions can be achieved by adjusting the coordination micro-environment with zinc phenolsulfonate and tetrabutylammonium 4-toluenesulfonate as a family of electrolytes. The theoretical understanding and in-situ spectroscopy analysis revealed that the favorable coordination of conjugated anions involved in hydrogn bond network minimizes the activate water molecules of hydrated zinc ion, thus improving the zinc/electrolyte interface stability to suppress the dendrite growth and side reactions. With the reversibly cycling of zinc electrode over 2000 h with a low overpotential of 17.7 mV, the full battery with polyaniline cathode demonstrated the impressive cycling stability for 10000 cycles. This work provides inspiring fundamental principles to design advanced electrolytes under the dual contributions of solvation modulation and interface regulation for high-performing zinc-based batteries and others. Zinc-based batteries suffer from the dendrite growth and surface passivation of zinc derived from the unfavourable deposition and side reactions. Here, the authors modulate the coordination chemistry of hydrated zinc ions via electrolyte-design and gain insights into the reversible cycling of long-lived zinc electrode.

Industrial CO 2 electrolysis via electrochemical CO 2 reduction has achieved progress in alkaline solutions, while the same reaction in acidic solution remains challenging because of severe hydrogen evolution side reactions, acid corrosion, and low target product selectivity. Herein, an industrial acidic CO 2 electrolysis to pure HCOOH system is realized in a proton-exchange-membrane electrolyzer using an acid-tolerant Bi-based metal-organic framework guided by a Pourbaix diagram. Significantly, the Faradaic efficiency of HCOOH synthesis reaches 95.10% at a large current density of 400 mA/cm 2 with a high CO 2 single-pass conversion efficiency of 64.91%. Moreover, the proton-exchange-membrane device also achieves an industrial-level current density of 250 mA/cm 2 under a relatively low voltage of 3.5 V for up to 100 h with a Faradaic efficiency of 93.5% for HCOOH production, which corresponds to an energy consumption of 200.65 kWh/kmol, production rate of 12.1 mmol/m 2 /s, and an energy conversion efficiency of 38.2%. These results will greatly aid the contemporary research moving toward commercial implementation and success of CO 2 electrolysis technology. This work develops an industrial-level CO 2 electrolysis system for formic acid production by constructing a proton exchange membrane electrolyzer with an acid-tolerant Bismuth metal-organic framework.

Tuning anionic solvation structures and dynamic processes at solid–liquid interfaces is critical yet challenging for stabilizing Zn metal negative electrodes in Zn-ion batteries, particularly due to the issue of dendrite formation and hydrogen evolution reaction. Here, we show that highly hydrated SO 4 2- can be effectively modulated under a strong magnetic field via the Paschen–Back effect on O-H vibrations, which reorients individual water molecules to manipulate Zn 2+ solvation and protonated water clusters (H 3 O + ). Molecular dynamics simulations and in situ Raman spectroscopy reveal that the hydrated SO 4 2- –H 2 O complexes promote Zn 2+ nucleation and deposition on the (002) plane, with preferential oxygen adsorption inhibiting two-dimensional Zn 2+ diffusion. Moreover, magnetizing the electrolyte disrupts the Grotthuss proton-transfer pathway, suppressing H 2 evolution and further reducing dendrite formation. By employing inexpensive permanent magnets without external power, this magnetization strategy offers a practical, energy-efficient route to enhance both the stability and performance of zinc-based rechargeable batteries. Dendrite growth and hydrogen evolution limit the stability of aqueous zinc metal batteries. Here, authors use a magnetic field to tune ion solvation and proton transfer, enabling uniform Zn deposition and suppressing side reactions, offering a simple strategy to boost battery performance.

Electrocatalytic acetylene semihydrogenation is a promising alternative to thermocatalytic acetylene hydrogenation due to its environmental benignity and economic efficiency, but its performance is far below that of the thermocatalytic reaction because of strong competition from side reactions, including hydrogen evolution, overhydrogenation and carbon–carbon coupling reactions. We develop N–heterocyclic carbene–metal complexes, with electron–rich metal centers owing to the strongly σ–donating N–heterocyclic carbene ligands, as electrocatalysts for selective acetylene semihydrogenation. Experimental and theoretical investigations reveal that the copper sites in N–heterocyclic carbene–copper facilitate the absorption of electrophilic acetylene and the desorption of nucleophilic ethylene, ultimately suppressing the side reactions during electrocatalytic acetylene semihydrogenation, and exhibit superior semihydrogenation performance, with faradaic efficiencies of ≥98 % under pure acetylene flow. Even in a crude ethylene feed containing 1 % acetylene (1 × 10 4 ppm), N–heterocyclic carbene–copper affords a specific selectivity of >99 % during a 100–h stability test, continuous ethylene production with only ~30 ppm acetylene, a large space velocity of up to 9.6 × 10 5  mL·g cat −1 ·h −1 , and a turnover frequency of 2.1 × 10 −2 s −1 , dramatically outperforming currently reported thermocatalysts. This study explores N–heterocyclic carbene copper complexes toward selective electrocatalytic reduction of acetylene to ethylene. The electron–rich copper sites were found to facilitate acetylene adsorption and ethylene desorption and achieved high activity and selectivity for ethylene production.