Acid Electrolyte Research Articles

Natural DNA-Derived Ultrafine Ir/Ir2P Hybrid on Porous N, P-Codoped Carbon for pH-Universal Energy-Saving Hydrogen Production Assisted by Electrocatalytic Hydrazine Oxidation

Due to the intrinsic slow kinetics and high potential of the anodic oxygen evolution reaction (OER), hydrazine oxidation reaction (HzOR) with ultralow potential is a viable substitute to combine the cathodic hydrogen evolution reaction (HER) for the energy-saving hydrogen generation. Therefore, it is a compelling demand to explore high-performance electrocatalysts for bifunctional HER and HzOR. Herein, natural DNA was employed to prepare the uniform and ultrafine Ir/Ir2P hybrids loaded on N, P-codoped porous carbon (Ir/PNPC) through a facile “mix-and-pyrolyze” approach. Benefitting from abundant heteroatom doping, large surface area and high degree of graphitization, Ir/PNPC only requires the ultrasmall potentials of -22/-347/-54 mV at 100 mA cm-2 for HER, 46/172/227 mV at 10 mA cm-2 for HzOR, and 167/836/864 mV at 100 mA cm−2 for the constructed two-electrode overall hydrazine splitting (OHzS) in the alkaline, neutral and acidic electrolytes, respectively, all exceeding Pt/C and also showing the remarkable energy-efficient superiority over the conventional water splitting. Furthermore, the OHzS system can be readily driven by the as-prepared direct N2H4/H2O2 fuel cell and commercial solar cell with decent H2 generation rate of 1.245 and 1.392 mmol h-1, respectively. This study provides lights on the preparation of the advanced pH-universal HER and HzOR bifunctional electrocatalysts by natural DNA and is also encouraging for the energy-saving H2 production.

A highly water-soluble phenoxazine quaternary ammonium compound catholyte for pH-neutral aqueous organic redox flow batteries

The pH-neutral aqueous redox flow battery (ARFB) is one of the most attractive flow batteries due to its non-corrosiveness, low-cost, and wider electrochemical stability window compared to those with acidic or alkaline electrolytes. However, there are few families of organic redox-active molecules available as catholyte materials for pH-neutral ARFBs. Herein, through incorporation of quaternary ammonium moiety into the redox-active phenoxazine nucleus, an organic catholyte material, N, N, N-trimethyl-2-(10H-phenoxazin-10-yl) ethan-1-aminium chloride (NEt-POZ) is achieved for pH-neutral ARFBs. The NEt-POZ has a high redox potential of 0.79 V versus SHE and rapid redox kinetics (0.23 cm s−1) as well as high water-solubility (∼2.6 M in H2O). Paired with a methyl viologen (MV) anolyte in the pH-neutral aqueous electrolyte, a viologen-phenoxazine ARFB full cell is assembled, which shows an open circuit voltage of ∼1.23 V. However, the results of long-term cycling experiments indicate low Coulomb efficiency and rapid declining capacity of the NEt-POZ catholyte. The mechanism analysis unveils that the unstable doubly oxidized tri-cations (NEt-POZ3+) formed via the disproportionation of radical di-cations (NEt-POZ2+) in solution readily react with chloride anions to form poly-chlorinated derivatives, which precipitate from the catholyte due to their poor water solubility, leading to a rapid decrease in capacity. When there is no chloride present in the electrolyte solution, highly reactive NEt-POZ3+ cations can interact with other counter-anions (such as sulfate and carbonate ions) and even water to form complex adducts.

Small Punch Test to Estimate the Threshold Stress in Aggressive Environments by Incremental Step Loading

The present work is a relevant advance in the validation of the incremental step loading technique (ASTM F1624 standard) when applied to Small Punch tests (SPT) for the threshold load determination of medium- and high-strength steels in aggressive environments, as a novel alternative to conventional time-consuming tests under constant load. It completes previous works by the authors on this topic, extending a methodology to estimate the threshold stress from SPT tests in aggressive environments, covering the whole range of hardness marked by ASTM F1624 as the main goal. This is achieved by calibrating a model of the material’s hardness by the use of a coefficient in function of it. For this purpose, four medium- and high-strength steels of 33, 35, 50 and 60 HRC (Hardness Rockwell C) are exposed to three different cathodic polarization hydrogen embrittlement environments of 1, 5 and 10 mA/cm2 in 1N H2SO4 acid electrolyte connected to a platinum anode. Threshold stresses in these circumstances are obtained by uniaxial specimens following ASTM F1624 and compared to their homologous threshold loads obtained by Small Punch tests according to the authors’ original methodology proposal. Finally, the aforementioned model, consisting of a correlation based on composing an elastic and a plastic part, is calibrated for a hardness ranging 33–60 HRC, this being the main original contribution of this work; the elastic part is dependent just on the elastic-to-plastic transition SPT load, while the plastic part is ruled by a material hardness-dependent coefficient. This technique supposes an advance in engineering tools, due to its applicability in situations of material shortage, such as in-service components, welded joints, local areas, complex geometries, small thicknesses, etc., often present in aerospace, automotive or oil–gas, among others.

Structural and Hydrophilic Properties of Nanoporous Aluminium Oxide Film as a Function of Voltage Anodization

Abstract The impact of voltage on the formation of nanopores through electrochemical anodization of high-purity aluminum was examined. The electrochemical bath was carefully prepared with oxalic acid electrolyte, while a 99.5% pure aluminum electrode served as the cathode and an aluminum template as the anode. The anodization process was conducted at room temperature, with voltage increments ranging from 20V to 65V, which was made possible by the in-house electrochemical cell. Notably, each incremental increase in voltage yielded a significant surge in current density, accompanied by a marked expansion in nanopore size, growing from approximately 35 nm to 125 nm. X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Rutherford backscattering spectrometry were used to characterize the films. A slight phase change was observed in the aluminum substrate's FCC structure after the anodization process, transitioning to a monoclinic structure at 39° and 45° for all applied potentials. The stoichiometry of the films was determined through RBS analysis. The nano pores' resulting morphology and phase composition were further examined using SEM and EDS, providing insights into their structural characteristics. Furthermore, the water contact angle of the anodized aluminum oxide samples was measured, revealing a range of approximately 85.16 to 61.01 degrees.

Atomically Dispersed Vanadium-Induced Ru-V Dual Active Sites Enable Exceptional Performance for Acidic Water Oxidation.

Regulating the catalytic reaction pathway to essentially break the activity/stability trade-off that limits RuO2 and thus achieves exceptional stability and activity for the acidic oxygen evolution reaction (OER) is important yet challenging. Herein, we propose a novel strategy of incorporating atomically dispersed V species, including O-bridged V dimers and V single atoms, into RuO2 lattices to trigger direct O-O radical coupling to release O2 without the generation of *OOH intermediates. Vn-RuO2 showed high activity with a low overpotential of 227 mV at 10 mA cm-2 and outstanding stability during a 1050 h test in acidic electrolyte. Operando spectroscopic studies and theoretical calculations revealed that compared with the V single atom-doping case, the introduction of the V dimer into RuO2 further decreases the Ru-V atomic distance and weakens the adsorption strength of the *O intermediate to the active V site, which supports the more energetically favorable oxygen radical coupling mechanism (OCM). Furthermore, the highly asymmetric Ru-O-V local structure stabilizes the surface Ru active center by lowering the valence state and increasing the resistance against overoxidation, which result in outstanding stability. This study provides insight into ways of increasing the intrinsic catalytic activity and stability of RuO2 by atomically dispersed species modification.

Atomically Dispersed Vanadium‐Induced Ru‐V Dual Active Sites Enable Exceptional Performance for Acidic Water Oxidation

AbstractRegulating the catalytic reaction pathway to essentially break the activity/stability trade‐off that limits RuO2 and thus achieves exceptional stability and activity for the acidic oxygen evolution reaction (OER) is important yet challenging. Herein, we propose a novel strategy of incorporating atomically dispersed V species, including O‐bridged V dimers and V single atoms, into RuO2 lattices to trigger direct O−O radical coupling to release O2 without the generation of *OOH intermediates. Vn−RuO2 showed high activity with a low overpotential of 227 mV at 10 mA cm−2 and outstanding stability during a 1050 h test in acidic electrolyte. Operando spectroscopic studies and theoretical calculations revealed that compared with the V single atom‐doping case, the introduction of the V dimer into RuO2 further decreases the Ru‐V atomic distance and weakens the adsorption strength of the *O intermediate to the active V site, which supports the more energetically favorable oxygen radical coupling mechanism (OCM). Furthermore, the highly asymmetric Ru−O−V local structure stabilizes the surface Ru active center by lowering the valence state and increasing the resistance against overoxidation, which result in outstanding stability. This study provides insight into ways of increasing the intrinsic catalytic activity and stability of RuO2 by atomically dispersed species modification.

Precise Construction of the Triple-Phase Boundary and Its Antiphosphate Poisoning Effect in the Confined Region.

As a critical component for the oxygen reduction reaction (ORR), platinum (Pt) catalysts exhibit promising catalytic performance in High-temperature-proton exchange membrane fuel cells (HT-PEMFCs). Despite their success, HT-PEMFCs primarily utilize phosphoric acid-doped polybenzimidazole (PA-PBI) as the proton exchange membrane, and the phosphoric acid within the PBI matrix tends to leach onto the Pt-based layers, easily causing toxicity. Herein, we first propose UiO-66@Pt3Co1-T composites with precisely engineered interfacial structures. The UiO-66@Pt3Co1-T exhibits an octahedral porous framework with uniform structural dimensions and even distribution of surface nanoparticles, which demonstrate superior ORR performance compared to commercial Pt/C. The unique structure and morphology of the composites also exhibit a favorable half-wave potential in different concentrations of phosphoric acid electrolyte, regulated by the phosphoric acid adsorption site and intensity.This finding suggests that the incorporation of Co could effectively modulate the Pt d-band center, thereby enhancing the ORR performance. Furthermore, the selective adsorption of phosphoric acid by ZrO2 enables precise control over the phosphoric acid distribution. Notably, the retention of the octahedral framework post high-temperature treatment facilitates the establishment of dual transport pathways for gases and protons, leading to a stable and efficient triple-phase boundary.

Electrodeposition of Ni-WC composite coatings: formation, structure and properties

Currently, electroplating is actively developing, and one of its promising areas is the study of composite electrochemical coatings (CEC). They are of great interest to the industrial sector, especially for mechanical engineering, due to their unique properties. CEC contain microscopic particles as additives that can significantly improve coating properties such as hardness and wear resistance. This is especially important for the manufacturing of high-quality parts of industrial mechanisms. These areas can lead to new advances in the development of better and more durable materials. In this work, composite coatings of nickel-tungsten carbide were obtained by the method of electrodeposition. The deposition was carried out in a sulfuric acid electrolyte with different concentrations of tungsten carbide. Formation of composite coatings was carried out at a concentration of dispersed particles in a sulfate electrolyte of 10 g/L. The coatings have no pores or cracks. Nickel and tungsten carbide phases were detected in the coatings by X-ray phase and micro-X-ray spectral analyses. Inclusions of WC in the nickel matrix lead to an increase in the microhardness of the coating by 10–15 times. Wear resistance was assessed under dry sliding friction with reciprocating motion; a decrease in the volume of worn material by 2–3 times was noted when tungsten carbide was added into the nickel matrix.

In-situ imaging and time-resolved investigation of local pH in electrocatalytic CO2 reduction

Local pH near the catalyst surface exerts a substantial influence on both catalytic selectivity and activity in electrocatalytic CO2 reduction (CO2RR). While the investigation of local pH remains challenging in the aspect of in-situ imaging and monitoring. In this study, a novel lateral-type surface-enhanced Raman spectroscopy (L-SERS) system with a wide pH testing range from acidic to alkaline, is developed for the in-situ observation of local pH distributions with high spatial and temporal resolution during CO2RR. Excellent in-situ imaging of local pH near the catalyst surface is obtained, showing good consistency with simulation results. Besides, the gradual pH elevation and stabilization can be monitored via this time-resolved local pH investigation. This study presents a direct visualization of local pH distribution and variation at the Nernst layer during CO2RR, providing direct evidence in local pH for the feasibility of acidic electrolyte and offering theoretical guidance for optimizing CO2RR conditions.

Porous N-Doped Carbon-encapsulated Iron as Novel Catalyst Architecture for the Electrocatalytic Hydrogenation of Benzaldehyde.

Carbon porous materials containing nitrogen functionalities and encapsulated iron-based active sites have been suggested as electrocatalysts for energy conversion, however their applications to the hydrogenation of organic substrates via electrocatalytic hydrogenation (ECH) remain unexplored. Herein, we report on a Fe@C:N material synthesized with an adapted annealing procedure and tested as electrocatalyst for the hydrogenation of benzaldehyde. Using different concentrations of the organic, and electrolysis coupled to gas chromatography experiments, we demonstrate that it is possible to use such architectures for the ECH of unsaturated organics. Potential control experiments show that ECH faradaic efficiencies >70 % are possible in acid electrolytes, while maintaining selectivity for the alcohol over the pinacol dimerization product. Estimates of product formation rates and turnover frequency (TOF) values suggest that these carbon-encapsulated architectures can achieve competitive performance in acid electrolytes relative to both base and precious metal electrodes.

Finite Element Analysis of Local pH Variations in Electrolysis with Porous Electrodes, Considering Water Self-Ionization.

A finite element model was developed to simulate ion fluxes and local pH changes within and around porous electrodes during the H2 evolution reaction (HER) in acidic electrolytes. This model is particularly characterized by its ability to simulate scenarios in which the local pH inside and near the cathode exceeds 7, even under bulk acidic conditions (e.g., pH = 1), by considering the self-ionization of water. Steady-state calculations using meshes with an appropriate spatial distribution inside and near the cathode revealed that the relationship between the local pH and the double-layer potential at the interface between the porous catalyst layer and the electrolyte domains changed notably when the local pH exceeded the threshold of 7. By comparing the fluxes of H+ and OH- ions at the interface and using the thickness of the catalyst layer as a variable, we determined that the presence of H+ ions within the pores or the supply of OH- ions from the pores to the interface was responsible for the characteristic change in the local pH observed for the porous electrode. The porous electrode model constructed in this study can potentially serve as a basis that can be extended to a wide range of electrolysis systems, including not only the HER, but also the reduction of CO2, H2O2, and O2, and even oxidation reactions such as the O2 evolution reaction.

Highly Tensile Strained Cu(100) Surfaces by Epitaxial Grown Hexagonal Boron Nitride for CO2 Electroreduction to C2+ Products.

Copper (Cu) has been considered as the most promising catalyst for the electrochemical conversion of CO2 to multicarbon (C2+) products. However, insufficient coverage of the *CO intermediate on the C2+ formation Cu(100) facet largely hinders the C-C coupling process and thus the C2+ conversion efficiency. Herein, we developed an epitaxial growth strategy to generate highly tensile-strained Cu(100) facets via the epitaxial growth of hexagonal boron nitride (hBN) on Cu(100) facets to promote *CO coverage for efficient CO2 to C2+ conversion. The highest ∼6% tensile strain on the Cu(100) facets was obtained by lattice mismatch between the Cu(100) and hBN(002) facets. Theory calculations indicated that tensile-strained Cu(100) facets deliver a notable d-band center upshift to enhance *CO adsorption. As a result, the obtained highly tensile-strained Cu(100) facets enabled an 8-fold improvement of *CO coverage and thus a 83.4% C2+ Faradaic efficiency at 1.2 A cm-2 in strongly acidic electrolyte (pH = 1).

Electrochemical Behavior of Tantalum Nitride Protective Layers for PEMFC Application

Proton Exchange Membrane Fuel Cells (PEMFCs) are promising technology to convert chemical energy from dihydrogen in electrical energy. HT-PEMFCs are working at high temperatures (above 120 °C) and with doped orthophosphoric acid H3PO4 PBI membranes. In such devices, bipolar metallic plates are used to provide reactive gas inside the fuel cell and collect the electrical current. The metallic elements used as bipolar plates, end plates, and interconnectors in acid electrolyte and gaseous fuel cells are severely damaged by a combination of oxidation (due in particular to the use of oxygen, whether pure or contained in the air) and corrosion (due in particular to acid effluents from the electrolyte). This degradation rapidly leads to the loss of the electrical conductivity of the metallic elements and today requires the use of very specific alloys, possibly coated with pure gold. The solution investigated in the present study is the use of a protective coating based on single-phase nitrides obtained by reactive magnetron sputtering or reactive HiPIMS (High-Power Impulse Magnetron Sputtering). The influence of the microstructure on the physical–chemical properties was studied. The electrochemical properties were quantified following two approaches. First, the corrosion current of the developed coatings was measured at room temperature and at higher temperatures using the Linear Sweep Voltammetry (LSV) technique. Then, Electrochemical Impedance Spectroscopy (EIS) measurements were performed to better identify and evaluate their corrosion-resistance performances.

Electroanalytical Studies on Codeposition of Cobalt with Ruthenium from Acid Chloride Baths

The aim of this study was to systematically analyze the influence of potential and the Co(II)–Ru(III) molar ratio on the electrochemical behavior of the Co–Ru system during codeposition from acidic chloride electrolytes. The equilibrium speciation of the baths was investigated spectrophotometrically and compared with theoretical calculations based on the stability constants of Co(II) and Ru(III) complexes. The codeposition of the metals was characterized using electroanalytical methods, including cyclic voltammetry, chronoamperometry, and anodic stripping linear voltammetry. The alloys obtained at different potentials were analyzed for their elemental composition (EDS, mapping), phase composition (XRD), and surface morphology (SEM). The morphology and composition of the alloys were mainly dependent on the deposition potential, which controlled the cobalt incorporation. Ruthenium–rich alloys were produced at potentials of −0.6 V and −0.7 V (vs. SCE). In these conditions, cobalt anomalously codeposited due to the formation of the CoOH+ intermediate, triggered by the intense hydrogen evolution on the ruthenium sublayer. Bulk cobalt electrodeposition began at a potential of around −0.8 V, resulting in the formation of cobalt-rich alloys. The early stages of the electrodeposition were investigated using different nucleation models. A transition from 2D progressive nucleation to 3D instantaneous nucleation at around −0.8 V was identified as being caused by cobalt incorporation. This was well correlated with electroanalytical data, partial polarization curves of alloy deposition, elemental mapping analysis, and the structure of the deposits.

Composite electrochemical coatings of Ni-CrB2 from sulfuric acid and sulfamate electrolytes: formation, structure and properties

Electrodeposited coatings are in demand in many industries: due to the high adhesive strength to the base metal, they can be applied to complex-shaped products, and the thickness of the deposited coating can be controlled. However, standard electrolytic coatings do not always meet the necessary operating requirements. In this case, the formation of composite electrolytic coatings, which consist in the modification of electrolytes by various dispersed particles, becomes an urgent task. These particles are introduced into the electrolyte and deposited together with the precipitate metals, which leads to changes in the coating properties. In this article, the structure, adhesive and corrosion properties of nickel-chromium diboride composite coatings obtained in the electrodeposition process are studied. Precipitation was carried out in sulfuric acid and sulfamate electrolytes with a concentration of dispersed chromium diboride particles of 10-40 g/l. The coatings consist of nickel and CrB2 phases. The adhesive strength of the coating with a steel base is satisfactory; chipping and peeling were not observed. The corrosion resistance of sulfamate electrolyte coatings is higher than that of the coatings obtained from sulfuric acid electrolyte due to the compactness of nickel precipitates. Chromium diboride in the coating provides 1.5-2 times greater corrosion resistance.

High Efficiency Alkaline Iodine Batteries with Multi‐Electron Transfer Enabled by Bi/Bi2O3 Redox Mediator

The multi‐electron transfer I‐/IO3‐ redox couple is attractive for high energy aqueous batteries. Shifting from an acidic to an alkaline electrolyte significantly enhances the IO3‐ formation kinetics due to the spontaneous disproportionation reaction, while the alkaline environment also offers more favorable Zn anode compatibility. However, sluggish kinetics during the reduction of IO3‐ persists in both acidic and alkaline electrolytes, compromising the energy efficiency of this glorious redox couple. Here, we establish the fundamental redox mechanism of the I‐/IO3‐ couple in alkaline electrolytes for the first time and propose that Bi/Bi2O3 acts as a redox mediator (RM) to “catalyze” the reduction of IO3‐. This mediation significantly reduces the voltage gap between charge/discharge from 1.6 V to 1 V with improved conversion efficiency and rate capability. By pairing the Zn anode and the Bi/Bi2O3 RM cathode, the full battery with I‐/IO3‐ redox mechanism achieves high areal capacity of 12 mAh cm‐2 and stable operation at 5 mAh cm‐2 for over 400 cycles.

High Efficiency Alkaline Iodine Batteries with Multi-Electron Transfer Enabled by Bi/Bi2O3 Redox Mediator.

The multi-electron transfer I-/IO3- redox couple is attractive for high energy aqueous batteries. Shifting from an acidic to an alkaline electrolyte significantly enhances the IO3- formation kinetics due to the spontaneous disproportionation reaction, while the alkaline environment also offers more favorable Zn anode compatibility. However, sluggish kinetics during the reduction of IO3- persists in both acidic and alkaline electrolytes, compromising the energy efficiency of this glorious redox couple. Here, we establish the fundamental redox mechanism of the I-/IO3- couple in alkaline electrolytes for the first time and propose that Bi/Bi2O3 acts as a redox mediator (RM) to "catalyze" the reduction of IO3-. This mediation significantly reduces the voltage gap between charge/discharge from 1.6 V to 1 V with improved conversion efficiency and rate capability. By pairing the Zn anode and the Bi/Bi2O3 RM cathode, the full battery with I-/IO3- redox mechanism achieves high areal capacity of 12 mAh cm-2 and stable operation at 5 mAh cm-2 for over 400 cycles.

Effect of Triton X-100 surfactant concentration on the wettability of polyethylene-based separators used in supercapacitors

Polyethylene-based separators are generally unsuitable for aqueous supercapacitors due to their poor wettability with the electrolyte, which impedes ion transport. However, incorporating Triton X-100 (2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) into the aqueous sulfuric acid (H2SO4) electrolyte improves the wettability of polyethylene and facilitates ionic movement through its pores. In this study, Triton X-100 was added to 1.0 M H2SO4 at various concentrations (0.122%–1.210% V/V) to evaluate its impact on supercapacitor performance. Supercapacitors were assembled using activated carbon-filled carbon cloth electrodes, each of the above electrolytes and polyethylene sheet separators. Scanning electron microscopy revealed that the carbon cloth exhibited a uniform fiber distribution and high surface area for activated carbon integration. The polyethylene separator displayed a porous structure with an average pore size of 165 ± 35 nm. Triton X-100 significantly reduced the water contact angle from 101.5° (without surfactant) to 30.2° (with 1.21% V/V Triton X-100), enhancing polyethylene’s wettability. This change from hydrophobic to hydrophilic characteristics enabled the formation of an electrical double layer at the separator/electrolyte interface, improving ionic transport. However, higher Triton X-100 concentrations increased the electrolyte's viscosity, which impeded ion movement. The highest specific capacitance of 55.3 F/g (at a scan rate of 0.005 V s−1) was achieved with 0.488% V/V Triton X-100. The specific capacitance varied with surfactant concentration in a complex manner, influenced by micelle formation and precipitation. These findings were corroborated by cyclic voltammetry and AC impedance spectroscopy.

Acidic "Water-in-Salt" Electrolyte Enables a High-Energy Symmetric Supercapacitor Based on Titanium Carbide MXene.

Titanium carbide MXene, Ti3C2Tx, exhibits ultrahigh capacitance in acidic electrolytes at negative potentials yet poor stability at positive potentials, resulting in low-energy densities for Ti3C2Tx-based symmetric supercapacitors. Utilizing "water-in-salt" electrolytes has successfully expanded the stable operation potential window of MXenes. However, this advancement comes at the cost of sacrificing their high capacitance in acidic electrolytes. In this work, we report an acidic "water-in-salt" (AWIS) electrolyte composed of sulfuric acid and saturated lithium halide, which effectively doubled the energy density of the Ti3C2Tx-based symmetric supercapacitor compared to those with bare acidic electrolytes. Specifically, the AWIS electrolyte successfully expanded the voltage window of the symmetric device to 1.1 V. A high specific capacitance of 112.34 F g-1 (at 10 mV s-1) was obtained due to the presence of proton redox. As a result, the symmetric device achieved a high-energy density of 19.1 Wh kg-1 and a high capacitance retention of 96.3% after 10,000 cycles. This work demonstrates the importance of designing stable and redox-active electrolytes for high-energy MXene-based symmetric supercapacitors.

Toward the Rechargeable Aqueous Zinc Ion Batteries with Improved Overall Performance: Electrolyte with Surface Adsorptive Additive.

Aqueous zinc-ion batteries (AZIBs) with slightly acidic electrolytes process advantages such as high safety, competitive cost, and satisfactory electrochemical performance. However, the failure behaviors of both electrodes, regarding zinc dendrite growth, interfacial parasitic reactions, and the collapse of cathode materials hinder the practical application of ZIBs. To alleviate the issues of both anode and cathode at the same time, D-xylose (DX) is introduced to the electrolyte as a multifunctional additive. As a result, the side reaction of the anode is suppressed and the metallic deposition behavior is regulated due to the hydrogen bonding network reconstruction and preferential surface adsorption of DX; for the MnO2 cathode, the DX adsorption can help the interfacial charge transfer and increase the reactive sites. Benefiting from these merits, DX-optimized Zn//Zn battery displays reveal a prolonged lifespan of 6912h and an ultra-high cumulative capacity of 17.28Ahcm-2 at 5mAcm-2. With the function of water reactivity suppression, the Coulombic efficiency reaches 99.91% at 2mAcm-2; the Zn||MnO2 full batteries exhibit excellent cyclability over 2000 cycles at 5C with an increased capacity of 118.9mAhg-1, indicating the dual functions to both of the electrodes for AZIBs.