Suppressing Hydrogen Evolution Research Articles

Regulating the space charge at interface by negative polar biomolecule enabling ultrastable Zn anode chemistry

The irreversibility of Zn metal anode arising from uncontrollable dendrite growth and hydrogen evolution reaction, especially at high current densities, has challenged the commercialization application of aqueous Zn-ion batteries. Here we report biomolecule additive, named xanthan gum, to solve these issues through making use of dissociated electronegative groups to reduce space charge near the anode-electrolyte interface, tuning solvation structure and form H2O-poor electrical double layer to regulate the Zn deposition behaviors. Meanwhile, the dissolved xanthan gum with multiple polar groups can break the association between H2O and Zn2+ to reconstruct solvated structures of Zn ions to suppress hydrogen evolution reaction (HER). Therefore, the Zn//Zn symmetric cells in ZnSO4 electrolyte with xanthan gum deliver an ultra-long cycle life (>4700 h), and also present excellent cycling performances in other electrolytes (Zn(OAc)2 and Zn(OTf)2). More importantly, a high coulombic efficiency of 99.7 % is achieved using Zn//Cu half cells tested and excellent cycling life for KVO//Zn full cells. This work provides a guidance to design the electrolyte additive for highly reversible Zn metal batteries.

Design of Bimetallic Boronene Structures Leveraging Neighboring Effects for Efficient Electrocatalytic CO2 Reduction Reaction

AbstractElectrocatalytic CO2 reduction (CO2RR) offers a promising avenue to address rising atmospheric CO2 levels by producing high‐value chemicals. However, the development of efficient, long‐lasting catalysts remains challenging. In this study, particle swarm optimization is employed to design a novel bimetallic boronene structure, thereby enhancing CO2RR activity through precise tuning of the metal‐substrate microenvironment. Through high‐throughput screening, seven CuMB4 (M = V, Zn, Nb, Ag, Cd, Ta, Au) monolayers are identified as promising CO2RR catalysts based on stability, conductivity, catalytic activity, and selectivity. These materials, characterized by hyper‐coordination and neighboring bimetallic effects, are proposed for synthesis via self‐assembled surface growth. Notably, CuZnB4 exhibited exceptional theoretical catalytic activity, characterized by remarkably low limiting potentials (UL) of −0.16 V for CH4 and −0.27 V for C2H4, as well as low kinetic barriers of 0.65 and 0.53 eV, respectively. The enhanced activity results from neighboring effects optimizing densely populated boron active sites and the ability to suppress hydrogen evolution reactions. Additionally, this study explored intrinsic properties influencing catalytic activity using volcano plots, descriptor analysis, and electron density evaluation. Unlike traditional catalysts prone to oxidation, CuMB4 varieties possess self‐activating properties, facilitating the conversion of *O/*OH to H2O and enhancing CO2 conversion. This research introduces robust CO2RR catalysts and provides insights into manipulating neighboring effects, thus guiding future catalyst design.

Optimizing Aqueous Zinc-Sulfur Battery Performance via Regulating Acetonitrile Co-Solvents and Carbon Nanotube Carriers.

Rechargeable aqueous zinc-sulfur batteries (AZSBs) are gaining attention due to their high energy density, ultra-stable discharge platform, and safety. However, poor liquid/solid reaction processes at the anode and cathode reduce reaction kinetics, and the severe dissolution of polysulfides causes shuttle effects during discharge/charge cycles, hindering practical applications. Improving performance requires optimizing both the cathode and electrolyte. Herein, we design an organic-inorganic hybrid electrolyte (zinc trifluoromethanesulfonate and trace iodine monomer dissolved in an acetonitrile/water co-solvent (AN-X)) and a partially exfoliated multi-walled carbon nanotube (PECNT) hosted sulfur (S@PECNTs) cathode for AZSBs. The sulfur is highly dispersed along the PECNTs with appropriate wettability at the electrode/electrolyte interface using AN-3 as the electrolyte. Meanwhile, this electrolyte inhibits hydrogen evolution at negative potentials and promotes uniform Zn ion stripping/plating. Expressively, the AN-3-based AZSB exhibits a high discharge capacity of 1370 mAh g-1 with excellent Coulombic efficiency (79.9 %), outstanding rate capability, and cycling performance. These improvements are attributed to the synergistic effect between the S@PECNTs and the AN-3 electrolyte, which reduces Rct to enhance reaction kinetics and blocks the dissolution and shuttle effect of polysulfides, ensuring a reversible reaction between zinc and sulfur.

Electrochemical investigations of decorated graphite felt electrodes with Nafion/TiO2 nanoparticles for vanadium redox flow battery: Improving electro-catalytic characteristics

The present study aimed to investigate the effect of Nafion/TiO2 nanoparticles as an electrocatalyst on the electrochemical behavior of graphite felt (GF) electrodes in a vanadium redox flow battery. Various electrochemical tests, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV), were conducted to assess the performance of these electrodes at different concentrations of nanoparticles (2–4 g l-1). Additionally, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy were employed to analyze the chemical composition, bonding, and morphology of the decorated electrodes, respectively. The CV results revealed several effects of TiO2 nanoparticles on the GF electrode, such as increased peak intensity and shifted peak sites. As the concentration of nanoparticles increased, the peak intensity rose by up to 44%. Moreover, the potentials of the decorated electrodes shifted towards the favorable side compared to the GF electrode, with changes ranging from 18 to 84%. Overall, the optimal concentration of TiO2 nanoparticles (3 g l-1) exhibited excellent electrode performance, characterized by the highest calculated diffusion coefficient, greater reversibility, enhanced electron transfer kinetics, improved stability, lower over-potential, and the lowest activation energy for redox reactions. EIS results demonstrated a significant decrease in polarization resistance (67.2–70.8%) for the decorated electrodes. Furthermore, LSV measurements indicated that the utilization of nano-electrocatalysts effectively inhibited hydrogen evolution at negative potentials.

Orderly Coating of Bilayer Polymer to Tailor Microenvironment for Efficient C−N Coupling Toward Highly Selective Urea Electrosynthesis

AbstractElectrosynthesis of urea from co‐reduction of carbon dioxide and nitrate is a promising alternative to the industrial process. However, the overwhelming existence of proton and nitrate as well as the insufficient supply of CO2 at the reaction interface usually result in complex product distributions from individual nitrate reduction or hydrogen evolution, instead of C−N coupling. In this work, we systematically optimize this microenvironment through orderly coating of bilayer polymer to specifically tackle the above challenges. Polymer of intrinsic microporosity is chosen as the upper polymer to achieve physical sieving, realizing low water diffusivity for suppressing hydrogen evolution and high gas permeability for smooth mass transfer of CO2 at the same time. Polyaniline with abundant basic amino groups is capable of triggering chemical interaction with acidic CO2 molecules, so that is used as the underlying polymer to serve as CO2 concentrator and facilitate the carbon source supply for C−N coupling. Within this tailored microenvironment, a maximum urea generation yield rate of 1671.6 μg h−1 mg−1 and a high Faradaic efficiency of 75.3 % are delivered once coupled with efficient electrocatalyst with neighboring active sites, which is among the most efficient system of urea electrosynthesis.

Breaking Mass Transport Limit for Hydrogen Evolution-Inhibited and Dendrite-Free Aqueous Zn Batteries.

It is commonly accepted that batteries perform better at low current densities below the mass-transport limit, which restricts their current rate and capacity. Here, it is demonstrated that the performance of Zn metal electrodes can be dramatically enhanced at current densities and cut-off capacities exceeding the mass-transport limit by using pulsed-current protocols. These protocols achieve cumulative plating/stripping capacities of 11.0 Ah cm-2 and 3.8 Ah cm-2 at record-high current densities of 80 and 160 mA cm-2, respectively. The study identifies and understands the promoted (002)-textured Zn growth and suppressed hydrogen evolution based on the thermodynamics and kinetics of competing reactions. Furthermore, the over-limiting pulsed-current protocol enables long-life Zn batteries with high mass loading (29 mgcathode cm-2) and high areal capacity (7.9 mAh cm-2), outperforming cells using constant-current protocols at equivalent energy and time costs. The work provides a comprehensive understanding of the current-capacity-performance relationship in Zn plating/stripping and offers an effective strategy for dendrite-free metal batteries that meet practical requirements for high capacity and high current rates.

Fluorine-regulated Cu catalyst boosts electrochemical reduction of CO2 towards ethylene production

Electrochemical reduction of carbon dioxide (CO2RR) into value-added multi-carbon (C2) products utilizing renewable energy is a promising way to reduce carbon emission and achieve carbon neutrality. However, rational design of catalysts towards high C2 products selectivity remains a formidable task. Herein, fluorine modified copper catalyst was synthesised by thermal anneal in the presence of ammonium fluoride and sequential annealing in argon atmosphere. The charge distribution and coordination environment on copper surface were adjusted by doped fluorine atoms, which enables the formation of key intermediates and their sequential evolution into ethylene. The catalyst achieves a remarkable Faradaic efficiency (FE) of 40.6 % for eCO2RR to ethylene and remains stable over 13 h. Density functional theory calculations indicates that the excellent CO2RR performance can be attributed to the suppressed hydrogen evolution on fluorine-doped copper catalyst. Our work brings a potential modification strategy of Cu-based catalyst for electrolytic CO2-to-C2 pathway.

P-d Orbital Hybridization Induced by CuGa2 Promotes Selective N2 Electroreduction

In the quest to align with industrial benchmarks, a noteworthy gap remains in the field of electrochemical nitrogen fixation, particularly in achieving high Faradaic efficiency (FE) and yield. The electrocatalytic nitrogen fixation process faces considerable hurdles due to the difficulty of cleaving the highly stable N≡N triple bond. Additionally, the electrochemical pathway for nitrogen fixation is often compromised by the concurrent hydrogen evolution reaction (HER), which competes aggressively for electrons and active sites on the catalyst surface, thereby reducing the FE of nitrogen reduction reactions (NRR). To surmount these challenges, this study introduces an innovative bimetallic catalyst, CuGa2, synthesized through p-d orbital hybridization to selectively facilitate N2 electroreduction. This catalyst has demonstrated a remarkable NH₃ yield of 9.82 μg h-1 cm-2 and an associated Faradaic efficiency of 38.25%. Our findings elucidate that the distinctive p-d hybridization interaction between Ga and Cu enhances NH3 selectivity by reducing the reaction energy barrier for hydrogenation and suppressing hydrogen evolution. This insight highlights the significance of the p-d orbital hybridization in optimizing the electrocatalytic performance of CuGa2 for nitrogen fixation.

High-Entropy Multiple-Anion Aqueous Electrolytes for Long-Life Zn-Metal Anodes.

Aqueous zinc-ion batteries (AZIBs) hold great promise for large-scale energy storage applications, however, their practical use is significantly hindered by issues such as zinc dendrite growth and hydrogen evolution. To address these challenges, we propose a high-entropy (HE) electrolyte design strategy that incorporates multiple zinc salts, aimed at enhancing ion kinetics and improving the electrochemical stability of the electrolyte. The interactions between multiple anions and Zn2+ increase the complexity of the solvation structure, resulting in smaller ion clusters while maintaining weakly anion-rich solvation structures. This leads to improved ion mobility and the formation of robust interphase layers on the electrode-electrolyte interface. Moreover, the HE electrolyte effectively suppresses hydrogen evolution and corrosion side reactions while facilitating uniform and reversible Zn plating/stripping processes. Impressively, the optimized electrolyte enables dendrite-free Zn plating/stripping for over 3000 h in symmetric cells and achieves a high Coulombic efficiency of 99.5% at 10 mA cm-2 in asymmetric cells. Inspiringly, full cells paired with Ca-VO2 cathodes demonstrate excellent performance, retaining 81.5% of the initial capacity over 1800 cycles at 5 A g-1. These significant findings highlight the potential of this electrolyte design strategy to improve the performance and lifespan of Zn-metal anodes in AZIBs.

Phase Engineering of ZnSe by Small Molecules as a High-Performance Protective Layer for Zn Anode.

The practical application of aqueous zinc ion batteries is still hampered by the side reactions and dendrite growth on Zn anode. Herein, the phase engineering of ZnSe coating layer by incorporating small molecules is developed to enhance the performance of Zn anode. The unique electronic structure of ZnSe⋅0.5N2H4 promises strong adsorption for Zn atoms and enhanced ability to inhibit hydrogen evolution, thereby promoting uniform Zn deposition and preventing by-product and dendrite growth. Meanwhile, fast Zn2+ transfer and deposition kinetics are also demonstrated by ZnSe⋅0.5N2H4. As a result, the ZnSe⋅0.5N2H4@Zn symmetric cell achieves long-term cycling stability up to 1900 h and 300 h at high current densities of 5 mA cm-2 and 20 mA cm-2, respectively. The assembled ZnSe⋅0.5N2H4@Zn||NH4V4O10 full cell presents outstanding cycling stability and rate capability. This work highlights the key role of crystal phase control of protective layer for high-performance zinc anode.

Stabilizing water and regulating interfacial electrostatic interaction with economical supporting salt for stable Zn metal anode

Developing rechargeable aqueous Zn batteries for large-scale energy storage is impeded by inadequate reversibility and stability of the Zn anode, primarily caused by parasitic reactions and heterogeneous deposition. This study proposes an economical electrolyte strategy to address these Zn-related issues. The addition of a supporting salt enhances the thermodynamic stability of water, reduces the number of highly reactive water molecules, and modulates the interfacial electrostatic interaction. This approach effectively suppresses hydrogen evolution reaction and uncontrolled deposition. Remarkably, the rationally proportioned electrolyte allows a high average Coulombic efficiency of 99.93% for 1000 cycles in a Zn||Cu battery and a prolonged lifespan exceeding 4800 h in Zn||Zn cells. The knock-on effect is that Zn||MnO2 pouch cells deliver stable cycling performance, demonstrating the viability of this approach for practical applications.

Preparation of a branched hierarchical Co3O4@Fe2O3 core–shell structure with high-density catalytic sites for efficient catalytic conversion of nitrate in wastewater to ammonia

This work employs a high-efficiency, low cost and environmentally friendly electrochemical nitrate reduction (NO3RR) strategy to realize the highly selective conversion of a typical environmental pollutant-nitrate to an extremely important chemical product-ammonia. To ensure high ammonia selectivity and Faradaic efficiency, a branched hierarchical Co3O4@Fe2O3 core–shell structure was synthesized on carbon cloth (CC) using a simple two-step hydrothermal method. After material characterization and parameter optimization, a nitrate conversion rate of 88.4 %, ammonia selectivity of 89.4 %, Faradaic efficiency of 87.2 % and NH3-N yield rate of 3810 μg h−1 cm−2 were obtained at Co3O4@Fe2O3|CC, which also displayed durability by retaining a high Faradaic efficiency of 79.3 % after six consecutive NO3RR cycles. Investigation of the mechanism reveals that active atomic *H plays a key role in the NO3RR. The excellent NO3RR performance of Co3O4@Fe2O3|CC is attributed to its branched hierarchical core–shell structure with large electrochemical surface area and fully exposed catalytic sites. In addition, both experimental and density functional theory (DFT) calculations indicate that the Co3O4@Fe2O3 core–shell structure is superior to Co3O4|CC and Fe2O3|CC in catalyzing NO3RR due to the synergistic effect between Co3O4 and Fe2O3. This synergistic effect can promote the adsorption of NO3–, release of NH3 and inhibition of hydrogen evolution, ensuring the highly selective and efficient conversion of NO3– to NH3. This work demonstrates that the morphology of an electrocatalyst can significantly affect its performance for the NO3RR, and has potential for practical application purposes.

Unlocking High Capacity and Reversible Alkaline Iron Redox Using Silicate-Sodium Hydroxide Hybrid Electrolytes.

Alkaline iron (Fe) batteries are attractive due to the high abundance, low cost, and multiple valent states of Fe but show limited columbic efficiency and storage capacity when forming electrochemically inert Fe3O4 on discharging and parasitic H2 on charging. Herein, sodium silicate is found to promote Fe(OH)2/FeOOH against Fe(OH)2/Fe3O4 conversions. Electrochemical experiments, operando X-ray characterization, and atomistic simulations reveal that improved Fe(OH)2/FeOOH conversion originates from (i) strong interaction between sodium silicate and iron oxide and (ii) silicate-induced strengthening of hydrogen-bond networks in electrolytes that inhibits water transport. Furthermore, the silicate additive suppresses hydrogen evolution by impairing energetics of water dissociation and hydroxyl de-sorption on iron surfaces. This new silicate-assisted redox chemistry mitigates H2 and Fe3O4 formation, improving storage capacity (199 mAh g-1 in half-cells) and coulombic efficiency (94 % after 400 full-cell cycles), paving a path to realizing green battery systems built from earth-abundant materials.

Mild polarization electric field in ultra-thin BN-Fe-graphene sandwich structure for efficient nitrogen reduction

The electrocatalytic N2 reduction reaction (NRR) is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient conditions. The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst, correct electron transfer direction, and electron tunneling distance between bare electrode and active sites. By coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method, an ultrathin sandwich catalyst, i.e., Fe atoms (polarized electric field layer) sandwiched between ultrathin (within electron tunneling distance) BN (catalyst layer) and graphene film (conducting layer), is fabricated for electrocatalytic NRR. The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure. The sandwich electrocatalyst NRR system achieve NH3 yield of 8.9 μg h−1 cm−2 and Faradaic Efficiency of 21.7%. The N2 adsorption, activation, and polarization electric field changes of three sandwich catalysts (BN-Fe-G, BN-Fe-BN, and G-Fe-G) during the electrocatalytic NRR are investigated by experiments and density functional theory simulations. Driven by applied voltage, the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

Spatial-confined effect of CuOx microneedles bundles on TiO2 nanotubes: Reinforcing the adsorption and enrichment of ultralow concentration nitrate for efficient NH3 electrosynthesis

Nitrate (NO3−) Electroreduction to produce NH3 offers an alternative approach to sustainable production of NH3. Yet it remains challenging to simultaneously improve the adsorption and enrichment of low-concentration NO3−. Here, bundles of CuOx microneedles on TiO2 nanotubes (NTs) were developed by a spatial-confined electrodeposition strategy, achieving 87.7 % or 98.4 % NH3 FE at −0.25 V or −0.45 V vs RHE in 2 or 10 mM NO3− electrolytes, respectively. Both in-situ spectroscopy and finite element analysis simulation demonstrated that CuOx microneedle bundles and its interface between TiO2 NTs not only greatly improve the enrichment of low concentration NO3− and its derived-NO2− and the diffusion of NH3 product, but also enhance the adsorption of NO2− and H2O to facilitate the hydrodeoxygenation of NO3− as well as inhibit hydrogen evolution reaction competition. This work will provide a promising avenue to develop electrocatalysts to realize efficient catalytic conversion of reactants at low concentrations.

Thiacalix[4]arene-Stabilized Sb/Ag Bimetallic Nanoclusters: Elucidating the Effects of Sb Doping on Electrocatalytic CO2 Reduction in Ag Clusters.

Accurately identifying the metal doping effects within heterogeneous catalysts presents a formidable challenge due to the complex nature of controlling the interfacial chemistry at the molecular level. Herein, we use two sets of atomically precise nanoclusters to demonstrate the impact of Sb doping on the electrocatalytic CO2 reduction activity in Ag nanoclusters. Leveraging the unique properties of the thiacalix[4]arene, we have pioneered a methodology for incorporating catalytic Ag1+ and Sb3+ sites, culminating in the synthesis of the pioneering Sb-Ag bimetallic cluster, Sb2Ag11. We refined this structure by replacing the two Sb3+ sites with Na+ sites, resulting in a Na2Ag10 cluster. Broadening our investigative scope, we isolated the core components from both Sb2Ag11 and Na2Ag10 and obtained two clusters: Sb2Ag4 and Ag4. The subtle compositional variations between two pairs of structurally analogous clusters, Sb2Ag11 and Na2Ag10, as well as Sb2Ag4 and Ag4, create opportunities to investigate how the Sb doping impacts the catalytic activity of Ag clusters. Clearly, compared to the undoped clusters, those doped with Sb exhibit higher catalytic current densities and enhanced CO selectivity. The theoretical calculations suggest that Sb doping can enhance the adsorption barrier of *H, thereby inhibiting hydrogen evolution activity and conversely promoting eCO2RR to CO activity.

Pb-MOF derived lead‑carbon composites for superior lead‑carbon battery

Lead‑carbon batteries (LCBs) provide considerable potential for large-scale energy storage, whereas exploring porous carbon negative additives with excellent mitigation of sulphation and parasitic hydrogen evolution remains challenging. Herein, lead‑carbon composite (PM@Cx) was prepared from simple pyrolysis of the electro-synthesized Pb-MOF precursor with waste lead paste as sacrificial anode for enhancing the performance of LCBs. The innovative transformation of waste lead paste into Pb-MOF enabled the uniform distribution of Pb atoms in the composite material and the in-situ generation of PbC heterojunction after pyrolysis. Benefitting from the presence of Pb nanoparticles and encapsulated structures, PM@Cx exhibits excellent inhibition of hydrogen evolution and increased affinity for carbon with active materials. Owing to the synergistic interaction of the above characteristics, the discharge capacity of the battery with PM@C500 reaches 3.75 Ah at 0.1C, which is 26.7 % enhancement compared to the control (2.96 Ah). The cycling lifespan is 6377 cycles at HRPSoC operating condition, 3 times of the control. This study provides innovative insights into the recycling of waste lead paste and the design of lead‑carbon composites for LCBs to inhibit negative sulphation and hydrogen evolution.

Investigation into the hydrogen inhibition mechanism of Platycladus orientalis leaf extract as a biodegradation inhibitor for waste aluminum-silicon alloy dust in wet dust collectors

This study investigates the risk of hydrogen explosion caused by waste metal dust encountering water in wet dust collectors. It proposes using renewable plant extracts to suppress hydrogen evolution from aluminum-silicon (Al-Si) alloy dust, aiming to achieve intrinsically safer production. Platycladus orientalis leaf extract (POLE) was prepared using water as a solvent. Hydrogen inhibition experiments, material characterization, and theoretical calculations were conducted to evaluate the effect of POLE on waste Al-Si dust. The inhibition experiments demonstrated that POLE exhibits excellent inhibitory performance. At a POLE concentration of 2.0 g/L, the hydrogen inhibition efficiency reaches 97.71 % after 22 h, with a reaction rate constant of 8.9708 × 10−5, approaching zero. This efficiency remained stable over 5 days. POLE formed a uniform, dense protective film on the Al-Si dust surface, with a contact angle of 99.23°. FTIR spectra revealed absorption peaks corresponding to POLE functional groups and Al-O bonds, indicating that successfully adsorption of POLE through both physical and chemical interactions. Finally, theoretical calculations were performed to further explain the hydrogen inhibition mechanism of POLE, supplementing and confirming the characterization data. This study inhibited hydrogen production from waste dust, offering a new approach to enhancing the hydrogen production rate from recycled Al scraps.

Insight into the corrosion inhibition mechanism of mild steel St1 in 2 M H2SO4 electrolyte by azithromycin

Mild steel is essential in modern industry due to its favorable mechanical properties and economic availability. However, its high susceptibility to corrosion, especially in acidic environments, poses a significant challenge, reducing service life, increasing operating costs, and raising the risk of failures. This study investigates the corrosion inhibition mechanism of mild steel St1 in a 2 M H2SO4 solution at various temperatures using the broad-spectrum antibiotic azithromycin (AZM). Experimental results indicate that AZM presence increases the polarization resistance of mild steel in the acidic solution. AZM acts as a mixed-type inhibitor, influencing the kinetics of both cathodic and anodic processes. The introduction of 200 mM AZM leads to an increase in the polarization resistance of the steel electrode in 2 M H2SO4 by up to 2.4 times. The inhibition mechanism involves forming a protective layer of protonated AZM forms on the negatively charged Fe surface. These protonated forms can also adsorb on cathodic areas, competing with hydronium ions (H3O+) and thereby inhibiting hydrogen evolution processes. The protective effect of AZM diminishes with increasing temperature of the corrosive environment, as confirmed by Monte Carlo simulations showing decreased adsorption energies for AZM and its protonated forms at higher temperatures. An assessment of the protective effect of 200 mM AZM showed that an increase in the temperature of the corrosive environment from 293 to 333 K leads to a decrease in the protective effect by almost 5.6 times. Quantum chemical calculations determined the reactivity of AZM and its protonated forms, identifying the molecular groups involved in the adsorption mechanism.

Achievement of advanced alkaline Ni-Zn batteries with good durability at a high areal capacity of 10 mAh cm−2 via the synergistic regulation of dual electrolyte additives

Though obvious advantages in terms of safety, cost, environmental compatibility and electrochemical performance (e.g, power and energy density), the commercial application of alkaline Ni-Zn batteries, a number of traditional aqueous batteries, is still under great restrictions owing to the poor durability (commonly less than 100 cycles). In this work, an effective electrolyte modification process using dual additives of hydroxy-rich carboxymethyl cellulose (CMC) that can inhibit hydrogen evolution reaction (HER) and suppress Zn dendrites, and benzyltrimethylammonium bromide (BTMAB) that can mitigate passivation and oxygen evolution reaction (OER) is developed. Meanwhile, our home made C coated ZnO (ZnO@C) microspheres were used as initial anode materials without the using of any other expensive composites. With a fixed areal charge capacity of 10 mAh cm−2, the flat type full cell matched with commercial Ni(OH)2 cathode can deliver a high average discharge capacity of ∼9.6 mAh cm−2 (corresponding to an average CE of 96 %) for a long lifespan of over 390 cycles, which drops to 8.2 mAh cm−2 at 400th cycle accompanied by the appearance of a peak in the charge curve. The cumulative discharge capacity of a full cell can reach ∼4,000 mAh cm−2 in 420 cycles’ cycling, much larger than that using commercial Zn/ZnO anode and the ZnO@C anode in unmodified or single additive modified electrolyte (less than 1,500 mAh cm−2).