Divalent Zinc Ions Research Articles

Enhancing Zn2+/H+ Joint Charge Storage in MnO2: Concurrently Tailoring Mn's Local Electron Density and O's p-Band Center.

Enhancing proton storage in the zinc-ion battery cathode material of MnO2 holds promise in promoting its electrochemical performance by mitigating the intense Coulombic interaction between divalent zinc ions and the host structure. However, challenges persist in addressing the structural instability caused by Jahn-Teller effects and accurately modulating H+ intercalation in MnO2. Herein, the doping of high-electronegativity Sb with fully occupied d-orbital in MnO2 is reported. The Sb doping strategy engenders the formation of Mn-O-Sb path in the structure with a strong dipole polarization field, which facilitates the delocalization of eg orbital electron in Mn and thus mitigates the Jahn-Teller effects. Simultaneously, adjusting the level of Sb doping in MnO2 leads to modulation of the p-band center of O, optimizing its interaction with hydrogen and thereby enhancing proton storage. Consequently, MnO2 doped with 6% Sb exhibits commendable performance in both rate capability and cycling endurance, delivering 113 mAh g-1 at 2 A g-1 after 2000 cycles. This investigation underscores the crucial role of electronic structural engineering in elevating the electrochemical performance of cathode materials for zinc-ion batteries.

Improving High-Voltage Cycling Stability and High-Rate Capability of Sodium-Ion Layered Cathode Oxides through Trace Amounts of Low-Valence Metals.

With the increasing demand for clean energy sources, the need for large-scale energy storage systems to ensure the stable output of renewable energy sources, such as wind and solar, has also increased. Sodium-ion batteries have emerged as a potential solution for these storage systems owing to their high energy density, abundance in the Earth's crust, and low cost. However, the larger atomic radius of sodium ions results in higher energy barriers for ion migration in cathode materials, which can affect the cycle life and rate performance of the battery. Therefore, developing a suitable structure that facilitates rapid sodiation and desodiation and maintains good cycling stability remains a significant challenge. This study aimed to reduce the content of trivalent manganese ions and minimize the impact of the Jahn-Teller effect to enhance the capacity retention of manganese-based layered oxides. Additionally, a series of P2-type Na0.78Li0.1ZnxNi0.15-xMn0.75O2 compounds were successfully synthesized through doping with divalent zinc ions. Structural analyses of the doped material indicated that Zn doping did not alter the crystal structure but increased the interlayer distance of the transition metals. Electrochemical performance tests revealed that appropriate Zn2+ doping promoted sodium-ion diffusion and improved the reversible capacity of the battery. This study provides a promising approach for developing sodium-ion batteries with rapid charging and discharging capabilities.

Kinetics‐Matched Electrode Design for Zn‐Metal Free Zinc Ion Batteries with High Energy Density and Stabilities

AbstractThe metal‐free rocking chair type Zn‐ion batteries (ZIBs) provide a promising approach toward the promotion of the Zn‐based batteries by circumventing the challenges including dendrite growth, hydrogen evolution reaction (HER), and surface corrosion. In order to sufficiently exploit the available capacity of this metal‐free batteries, it is necessary to effectively enhance the sluggish reaction kinetics of divalent zinc ions. Equally important is to achieve a balance in the kinetics between cathode and anode. Here, hetero‐valent doping and oxygen vacancy engineering are employed to effectively enhance the reaction dynamics of V2O5 cathodes and MoO3 anodes. Moreover, to the best of the knowledge, for the first time, the strategy of kinetics matching between the two electrodes is applied to the construction of rocking‐chair zinc ion batteries, enabling the cathode and anode to share similar zinc ion migration rates, and achieving a high energy density of up to 58.7 Wh kg−1 (based on the total electrode mass) as well as excellent cycling stability (90% after 500 cycles). This work demonstrates the importance of kinetics matching in zinc‐ion full‐cell performance and pave a benefitable avenue to for the pursuit of advanced multi‐valent metal‐ion batteries.

Electrical conductivity of potassium polyferrite doped with doubly charged cations

To clarify the charge compensation mechanism and the way of alloying additives placement, the authors synthesised samples of potassium βʺ-polyferrites with a wide range of mole fraction of introduced doubly charged cations. For these samples, the authors measured the electronic conductivity, cationic conductivity, and performed X-ray diffraction (XRD) analysis. The authors identified the charge compensation mechanism in potassium β″-polyferrite when doped with divalent ions of calcium, strontium, magnesium, and zinc. The charge compensation mechanisms differ depending on the radius of the introduced doubly charged ion. The results of cationic conductivity measurements of potassium β″-polyferrites show the mobility reduction of large calcium and strontium cations of potassium ions. Such additives are quite promising for improving the mechanical strength and thermal stability of the catalyst granules. They also increase the chemical stability of the contact granules. Corrosion resistance of pellets is a critical parameter. It determines the period of effective functioning of the catalyst. The data on electronic conductivity allow one to conclude that the introduction of Mg2+, Zn2+ cations sharply reduces the electron exchange in the structure of potassium β″-polyferrite. This should inevitably cause deactivation of the catalyst, while Ca2+ and Sr2+ ions do not reduce the electron transfer rate. Moreover, using the proposed approach will intensify the research process.

Physiological responses and lipid accumulation of freshwater microalgae Chlorella sorokiniana under short-term zinc stress in water solution

As a potential toxic element, zinc exhibits strong environmental mobility and bioavailability, rendering it a subject of profound concern as a highly toxic pollutant. In this study, the toxic effects of divalent zinc ion (Zn2+) with high concentrations at 5, 10, 15, 20, and 25 mg/L on the physiological states of Chlorella sorokiniana were investigated, including growth inhibition, photosynthesis, oxidative damage, and lipid accumulation. The results unequivocally revealed a substantial inhibition of C. sorokiniana growth in response to above 5 mg/L Zn2+ exposure. The photosynthetic activity and photosynthetic pigment content of C. sorokiniana declined with the increase of Zn2+. However, the photosynthetic activity slowly recovered after 72 h of exposure. Zn2+ induced a rapid increase in reactive oxygen species (ROS) within the microalgae, subsequently stimulating superoxide dismutase activity. Nevertheless, the uneliminated excess ROS disrupted the cell membrane, leading to the production of malondialdehyde. Furthermore, Zn2+ at concentrations of 5 and 20 mg/L positively affected the lipid accumulation, resulting in the highest 4.10 mg/L/d lipid production.

GPR39 regulated spinal glycinergic inhibition and mechanical inflammatory pain.

G protein-coupled receptor 39 (GPR39) senses the change of extracellular divalent zinc ion and signals through multiple G proteins to a broad spectrum of downstream effectors. Here, we found that GPR39 was prevalent at inhibitory synapses of spinal cord somatostatin-positive (SOM+) interneurons, a mechanosensitive subpopulation that is critical for the conveyance of mechanical pain. GPR39 complexed specifically with inhibitory glycine receptors (GlyRs) and helped maintain glycinergic transmission in a manner independent of G protein signalings. Targeted knockdown of GPR39 in SOM+ interneurons reduced the glycinergic inhibition and facilitated the excitatory output from SOM+ interneurons to spinoparabrachial neurons that engaged superspinal neural circuits encoding both the sensory discriminative and affective motivational domains of pain experience. Our data showed that pharmacological activation of GPR39 or augmenting GPR39 interaction with GlyRs at the spinal level effectively alleviated the sensory and affective pain induced by complete Freund's adjuvant and implicated GPR39 as a promising therapeutic target for the treatment of inflammatory mechanical pain.

RNA-binding peptide and endosomal escape-assisting peptide (L2) improved siRNA delivery by the hexahistidine-metal assembly.

Small interfering RNAs (siRNAs), comprising 21-23 nucleotides, function by complementary binding to specific mRNA sequences, thereby suppressing target protein expression. Despite their vast potential in disease therapy, siRNAs face challenges due to their susceptibility to degradation and high electronegativity, rendering them unstable in the bloodstream and impeding their passage across endothelial barriers. Moreover, successful intracellular delivery necessitates overcoming endosomal entrapment, posing a significant hurdle for carrier material development. In this study, leveraging the strong affinity of histidine oligomers (His6) for metal ions, we engineered nanoparticles (HmA) by gentle assembly with divalent zinc ions under pH = 8 conditions. We designed the RNA-binding functional peptide L2-NTD to enhance siRNA stability and delivery efficiency when complexed with HmA. The resulting siRNA+L2-NTD@HmA nanoparticles were formed via in situ encapsulation, ensuring efficient siRNA delivery into cells with minimal cytotoxicity and degradation. This approach presents a novel strategy for the design and artificial fabrication of carriers for effective RNA delivery.

PH-responsive on-demand release of eugenol from metal-organic frameworks for synergistic bacterial killing.

Bacterial infections are a big challenge in clinical treatment, making it urgent to develop innovative antibacterial systems and therapies to combat bacterial infections. In this study, we developed a novel MOF-based synergistic antibacterial system (Eu@B-UiO-66/Zn) by loading a natural antibacterial substance (eugenol) with hierarchically porous MOF B-UiO-66 as a carrier and further complexing it with divalent zinc ions. Results indicate that the system achieved a controlled release of eugenol under pH responsive stimulation, with the complexation ability of eugenol and Zn2+ ions as a switch. Due to the destruction of a coordination bond between eugenol and Zn2+ ions by an acidic medium, the release of eugenol loaded in Eu@B-UiO-66/Zn reached 80% at pH 5.8, which was significantly higher than that under pH 8.0 (51%). Moreover, the inhibitory effect of Eu@B-UiO-66/Zn against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) after 24 h was 96.4% and 99.7%, respectively, owing to the synergistic antibacterial effect of eugenol and Zn2+ ions, which was significantly stronger than free eugenol and Eu@B-UiO-66. We hope that this strategy for constructing responsive MOF-based antibacterial carriers could have potential possibilities for the application of MOF materials in antibacterial fields.

Biochemical responses of freshwater microalgae Chlorella sorokiniana to combined exposure of Zn(Ⅱ) and estrone with simultaneous pollutants removal

With the development of livestock industry, contaminants such as divalent zinc ions (Zn (Ⅱ)) and estrone are often simultaneously detected in livestock wastewater. Nevertheless, the combined toxicity of these two pollutants on microalgae is still unclear. Moreover, microalgae have the potential for biosorption and bioaccumulation of heavy metals and organic compounds. Thus, this study investigated the joint effects of Zn (Ⅱ) and estrone on microalgae Chlorella sorokiniana, in terms of growth, photosynthetic activity and biomolecules, as well as pollutants removal by algae. Interestingly, a low Zn (Ⅱ) concentration promoted C. sorokiniana growth and photosynthetic activity, while the high concentration experienced inhibition. As the increase of estrone concentration, chlorophyll a content increased continuously to resist the environmental stress. Concurrently, the secretion of extracellular polysaccharides and proteins by algae increased with exposure to Zn (Ⅱ) and estrone, reducing toxicity of pollutants to microalgae. Reactive oxygen species and superoxide dismutase activity increased as the increase of pollutant concentration after 96 h cultivation, but high pollutant concentrations resulted in damage of cells, as proved by increased MDA content. Additionally, C. sorokiniana displayed remarkable removal efficiency for Zn (Ⅱ) and estrone, reaching up to 86.14% and 84.96% respectively. The study provides insights into the biochemical responses of microalgae to pollutants and highlights the potential of microalgae in pollutants removal.

Zeolites with Divalent Ions as Carriers in the Delivery of Epigallocatechin Gallate.

Epigallocatechin gallate (EGCG) is a compound with very high therapeutic potential in the treatment of osteoporosis and cancer. The disadvantages of this compound are its low stability and low bioavailability. Therefore, carriers for EGCG are sought to increase its use. In this work, new carriers are proposed, i.e., zeolites containing divalent ions of magnesium, calcium, strontium, and zinc in their structure. EGCG is retained on the carrier surface by strong interactions with divalent ions. Due to the presence of strong interactions, EGCG is released in a controlled manner from the carrier-ion-EGCG drug delivery system. The results obtained in this work confirm the effectiveness of the preparation of new carriers. EGCG is released from the carriers depending on the pH; hence, it can be used both in osteoporosis and in the treatment of cancer. The divalent ion used affects the sorption and release of the drug. The obtained results indicate the great potential of the proposed carriers and their advantage over the carriers described in the literature.

Preparation of quinoa bran dietary fiber-based zinc complex and investigation of its antioxidant capacity in vitro.

In order to improve the economic utilization of quinoa bran and develop a safe and highly available zinc ion biological supplement. In this study, a four-factor, three-level response surface optimization of quinoa bran soluble dietary fiber (SDF) complexation of zinc was studied. The effect used four factors on the chelation rate was investigated: (A) mass ratio of SDF to ZnSO4.7H2O, (B) chelation temperature, (C) chelation time, and (D) pH. Based on the results of the single-factor test, the four-factor three-level response surface method was used to optimize the reaction conditions. The optimal reaction conditions were observed as mentioned here: the mass ratio of quinoa bran SDF to ZnSO4.7H2O was 1, the reaction temperature was 65°C, the reaction time was 120 min, and the pH of the reaction system was 8.0. The average chelation rate was 25.18%, and zinc content is 465.2 μg/g under optimal conditions. The hydration method rendered a fluffy quinoa bran SDF structure. The intramolecular functional groups were less stable which made the formation of the lone pairs of electrons feasible to complex with the added divalent zinc ions to form a quinoa bran soluble dietary fiber-zinc complex [SDF-Zn(II)]. The SDF-Zn(II) chelate had higher 2,2-diphenylpicrylhydrazyl (DPPH), ABTS+, hydroxyl radical scavenging ability, and total antioxidant capacity. Therefore, metal ion chelation in dietary fiber is of biological importance.

PCB-waste derived resin as a binary ion exchanger for zinc removal: Isotherm modelling and adsorbent optimization

Effective removal of heavy metals from wastewaters can enable increased reuse of treated wastewater and reduce water scarcity worldwide. This paper describes the results of an initial study on zinc removal using waste-derived aluminosilicate-based material by binary ion exchange with calcium and potassium. About 2 mmol/g of zinc removal adsorption capacity was demonstrated using the aluminosilicate resin. Seven equilibrium isotherm models have been analyzed using the zinc adsorption data; the best fit to the experimental values based on the lowest SSE error was the SIPS model. A mechanism between zinc adsorption and the calcium and potassium desorption has been developed and modelled and is confirmed based on the mass balance analysis between the divalent calcium ions and the monovalent potassium ions exchanged with the divalent zinc ions adsorbed. Desorption studies using isotherm model equations for the calcium and potassium data further confirmed the mechanism. Regeneration was over 80% per cycle for three acid regenerations, indicating the zinc can be recovered for re-use. Furthermore, optimization using the SIPS model showed the minimum amount of adsorbent required using a two-stage reactor system is much lower, proving the need for a two-stage reactor to make the system more economical. Future experiments on multicomponent analysis and further optimization will help develop this adsorbent for real water systems.

Measuring Zn2+ binding to DNA and corresponding structural changes using circular dichroism and ICP-OES.

Zinc is the second most abundant transition metal on the body. While the nature of zinc binding to DNA remains unclear it is known that zinc binding causes measureable structural changes. It is not established whether the divalent zinc ions are specifically bound to a particular site within DNA or diffusively bound. By combining CD (circular dichroism) spectroscopy measurements of DNA with ICP-OES (Inductively coupled plasma optical emission spectroscopy) measurements of ions binding to DNA, changes caused by the zinc binding can be monitored. CD spectroscopy measurements oversee changes in the DNA structure, while ICP-OES can quantify the amount of zinc ions bound to the phosphate groups of DNA. This will provide important insight on the effects of transition metal divalent ion binding on DNA structure.

Colorful ultralong room-temperature phosphorescence in dual-ligand metal-organic framework

Long afterglow organic-inorganic hybrid materials have attracted much attention in recent years and are widely used in information security, biological imaging and many other fields. Since up-conversion long-persistence materials are promising for bio-optical imaging due to their high penetration depth and elimination of autofluorescence background, it is highly desirable to combine down-conversion and up-conversion pathways to obtain smart materials with excitation-dependent tunable room-temperature phosphorescence properties. In this work, a metal-organic framework (Zn-DCPS-BIMB), consisting of divalent zinc ions, o-bis(imidazol-1-ylmethyl)benzene and 4,4′-dicarboxydiphenylsulfone, is designed to stabilize triplet excitons, coordinate the emission of different ligands, and endow materials with tunable emission color and up-conversion properties via heavy atoms effects promoting single-triplet orbital coupling and intersystem crossing.

Halogen Conversion-Intercalation Cathode for Zinc-Ion Battery

Zinc-ion batteries (ZIBs) are a promising class of batteries for grid-scale electrochemical energy storage owing to their low cost, easy fabrication and high operational safety. ZIBs adoption have been hampered by a lack of efficient cathode materials, which is due to the high polarisation of divalent zinc ions, which leads to strong binding with the host lattice in combination with slow solid-state migration. In this contribution, I describe a strategy that eliminates the involvement of Zn2+ within cathode chemistry. The method employs confined halogen within a carbon structure as the cathode electrode, with the halogen ions acting as both charge carriers and redox centres. The benefits of using confined halogen within the carbon structure as a cathode are (i) elimination of the irreversible binding of Zn2+ to the host structure within the cathode chemistry, (ii) the provision of substantial extra charge through their conversion-intercalation/adsorption process and (iii) they do not have to diffuse to the surface from bulk electrolyte as they are already inside the carbon structure aqueous ZIBs that utilize a conversion chemistry cathode. I'll illustrate how the cathode composite's Zn halide and carbon structure are completely different, resulting in electrochemical energy storage devices that are fundamentally different (battery vs supercapacitor). The use of graphite in the composite electrode resulted in battery-like behaviour, with the voltage plateau being related to the halogen species' standard potential. Using a mix of electrochemical and in-situ spectroscopic approaches, the halogen reaction process was revealed. This fundamental understanding will be used as a starting point for the development of efficient aqueous ZIBs that utilize a conversion chemistry cathode.

Interface Coordination Stabilizing Reversible Redox of Zinc for High-Performance Zinc-Iodine Batteries.

Aqueous Zn batteries (AZBs) have attracted extensive attention due to good safety, cost-effectiveness, and environmental benignity. However, the sluggish kinetics of divalent zinc ion and the growth of Zn dendrites severely deteriorate the cycling stability and specific capacity. The authors demonstrate modulation of the interfacial redox process of zinc via the dynamic coordination chemistry of phytic acid with zinc ions. The experimental results and theoretical calculation reveal that the in-situ formation of such inorganic-organic films as a dynamic solid-electrolyte interlayer is efficient to buffer the zinc ion transfer via the energy favorable coordinated hopping mechanism for the reversible zinc redox reactions. Especially, along the interfacial coating layer with porous channel structure is able to regulate the solvation structure of zinc ions along the dynamic coordination of the phytic acid skeleton, efficiently inhibiting the surface corrosion of zinc and dendrite growth. Therefore, the resultant Zn anode achieves low voltage hysteresis and long cycle life at rigorous charge and discharge circulation for fabricating highly robust rechargeable batteries. Such an advanced strategy for modulating ion transport demonstrates a highly promising approach to addressing the basic challenges for zinc-based rechargeable batteries, which can potentially be extended to other aqueous batteries.

High zinc-ion intercalation reaction activity of MoS2 cathode based on regulation of thermodynamic metastability and interlayer water

Divalent zinc-ion with sluggish reaction kinetics limits the choice of cathode materials for aqueous zinc-ion batteries. Metastable 1T-MoS2 shows higher electrochemical activity of ion intercalation reaction in comparison with the thermodynamically stable 2H-MoS2. Herein, the monolayer water inserted 1T-MoS2 nanosheets have been prepared by solvothermal method, investigated as the cathode in zinc-ion batteries. The monolayer water between interlayers can not only expand interlayer spacing but also maintain the metastable structure of 1T-MoS2 nanosheets, conducing to reduce activation energy for Zn2+ intercalation and enhance specific capacity. The obtained 1T-MoS2 cathode with changed 4d orbitals of Mo4+ delivers specific capacity of 164.1 mAh g−1 at 100 mA g−1 and 120.1 mAh g−1 at 2000 mA g−1, which is 6–8 times that of 2H-MoS2 cathode. The open circuit voltage of the 1T-MoS2 cathode increased to 0.96 V compared with 0.64 V of 2H-MoS2. The DFT calculations are executed to explore the influence of interlayer water on interlayer spacing and the energy storage behavior of Zn2+. Combined with the experimental results and DFT calculations, the roles of the crystalline phase and interlayer water in electronic configuration varies of Mo 4d orbitals are discussed and the Zn2+ intercalation process and storage mechanism are revealed.

Tuning Zn2+ coordination tunnel by hierarchical gel electrolyte for dendrite-free zinc anode

Aqueous zinc-ion batteries (ZIBs) are perceived as one of the most upcoming grid-scale storage systems. However, the issues of electrode dissolution, dendrite formation, and corrosion in traditional liquid electrolytes have plagued its progress. In this work, Zn dendrite growth and side reactions are effectively suppressed by a highly-confined tannic acid (TA) modified sodium alginate (SA) composite gel electrolyte (TA-SA). The ion-confinement effect is enhanced by divalent zinc ions coordinated with carboxyl groups and chelated with phenolic hydroxyl groups, thus guiding and regulating Zn deposition to achieve steady zinc plating/stripping behavior. As a consequence, the Zn/TA-SA/NH4V4O10 full cells deliver a high specific capacity of 238.6 mAh g−1 and maintain 94.51% over 900 cycles at 2 A g−1. Notably, after resting over 5 d, the capacity can be stabilized with a capacity retention of 97.25% after 200 cycles at 2 A g−1. This highly-confined and hydrogen bond-strengthened gel electrolyte may provide an effective strategy for the future development of quasi-solid-state metal batteries.

Aluminum-ion intercalation and reduced graphene oxide wrapping enable the electrochemical properties of hydrated V2O5 for Zn-ion storage

Aqueous zinc-ion batteries (AZIBs) have the characteristics of high theoretical specific capacity, wide source and high safety, and become a very promising energy storage equipment. Due to the larger solvation radius and stronger electrostatic interaction of divalent zinc ions, the cathode materials need to have larger space and more stable structure. The ions or molecules are pre-inserted between the vanadium oxide layers as pillars, which can provide large layer spacing and facilitate the insertion/extraction process and diffusion of zinc ions, but their performance is limited due to their low conductivity and solubility. By combining it with carbon materials with high conductivity and strong chemical stability, it can make up for these shortcomings and greatly improve the electrochemical performance. Herein, aluminum-ion intercalated hydrated V2O5 (AlxV2O5·nH2O, abbreviated as AlVOH)/reduced graphene oxide (AlVOH/rGO) composite was synthesized by a one-step hydrothermal method to improve the Zn ion storage properties of hydrated V2O5 (VOH). The composite material has a large layer spacing of 13.3 Å, and the composite of rGO not only enhances its electrical conductivity, but also protects the electrode active material to a certain extent. As expected, AlVOH/rGO has good cycle stability and rate performance, which shows a specific capacity of 405 mA h·g−1 at 0.1 A·g−1 and has no significant energy attenuation after 100 cycles.

Hygroscopic Double‐Layer Gel Polymer Electrolyte toward High‐Performance Low‐Temperature Zinc Hybrid Batteries

AbstractAqueous zinc hybrid batteries have been rapidly developed to overcome the sluggish kinetics of divalent zinc ions in the cathode of Zn‐based batteries. However, their cycle life is limited by water decomposition during the operation, specifically at low current rate for long‐term cycles. Herein, we propose a zinc hybrid battery with excellent adaptability of low‐temperature, at which the water decomposition is seriously restrained. The battery involves a hygroscopic double‐layer gel polymer electrolyte, in which one layer close to the LiFePO4 cathode provides Li+, and the other layer close to the Zn anode provides Zn2+. The use of the double‐layer electrolyte can both weaken the water reactivity and increase the salt concentration, leading to a high‐performance of the batteries. It enables the hybrid batteries to operate at −20 °C and achieve stability for over 300 cycles with a capacity retention of 85.14 % and Coulombic efficiency of ∼100 % at a low current rate of 85 mA g−1. Moreover, the spontaneous hygroscopic system, opposite to that of “water‐in‐salt”, can efficiently reduce manufacturing costs and improve ionic conductivity. This provides an advanced pathway for designing electrolytes to achieve high‐performance and low‐cost batteries with excellent adaptability of low‐temperature.