Showing papers on "Zinc published in 2018"
TL;DR: This work demonstrates that an aqueous electrolyte based on Zn and lithium salts at high concentrations is a very effective way to address irreversibility issues and brings unprecedented flexibility and reversibility to Zn batteries.
Abstract: Metallic zinc (Zn) has been regarded as an ideal anode material for aqueous batteries because of its high theoretical capacity (820 mA h g–1), low potential (−0.762 V versus the standard hydrogen electrode), high abundance, low toxicity and intrinsic safety. However, aqueous Zn chemistry persistently suffers from irreversibility issues, as exemplified by its low coulombic efficiency (CE) and dendrite growth during plating/ stripping, and sustained water consumption. In this work, we demonstrate that an aqueous electrolyte based on Zn and lithium salts at high concentrations is a very effective way to address these issues. This unique electrolyte not only enables dendrite-free Zn plating/stripping at nearly 100% CE, but also retains water in the open atmosphere, which makes hermetic cell configurations optional. These merits bring unprecedented flexibility and reversibility to Zn batteries using either LiMn2O4 or O2 cathodes—the former deliver 180 W h kg–1 while retaining 80% capacity for >4,000 cycles, and the latter deliver 300 W h kg–1 (1,000 W h kg–1 based on the cathode) for >200 cycles.
1,721 citations
TL;DR: A design with sodium vanadate hydrate as cathode is shown, allowing simultaneous proton and zinc-ion insertion/extraction and enhanced performance and the quasi-solid-state zinc/sodium vanadates hydrate battery is a good candidate for flexible energy storage device.
Abstract: Rechargeable aqueous zinc-ion batteries are promising energy storage devices due to their high safety and low cost. However, they remain in their infancy because of the limited choice of positive electrodes with high capacity and satisfactory cycling performance. Furthermore, their energy storage mechanisms are not well established yet. Here we report a highly reversible zinc/sodium vanadate system, where sodium vanadate hydrate nanobelts serve as positive electrode and zinc sulfate aqueous solution with sodium sulfate additive is used as electrolyte. Different from conventional energy release/storage in zinc-ion batteries with only zinc-ion insertion/extraction, zinc/sodium vanadate hydrate batteries possess a simultaneous proton, and zinc-ion insertion/extraction process that is mainly responsible for their excellent performance, such as a high reversible capacity of 380 mAh g–1 and capacity retention of 82% over 1000 cycles. Moreover, the quasi-solid-state zinc/sodium vanadate hydrate battery is also a good candidate for flexible energy storage device. Rechargeable zinc-ion batteries are promising energy storage devices but suffer from the limited choice of positive electrodes. Here Niu and co-workers show a design with sodium vanadate hydrate as cathode, allowing simultaneous proton and zinc-ion insertion/extraction and enhanced performance.
1,010 citations
TL;DR: The results suggest that the H2 O-solvated Zn2+ possesses largely reduced effective charge and thus reduced electrostatic interactions with the V2 O5 framework, effectively promoting its diffusion.
Abstract: Low-cost, environment-friendly aqueous Zn batteries have great potential for large-scale energy storage, but the intercalation of zinc ions in the cathode materials is challenging and complex. Herein, the critical role of structural H2O on Zn2+ intercalation into bilayer V2O5·nH2O is demonstrated. The results suggest that the H2O-solvated Zn2+ possesses largely reduced effective charge and thus reduced electrostatic interactions with the V2O5 framework, effectively promoting its diffusion. Benefited from the “lubricating” effect, the aqueous Zn battery shows a specific energy of ≈144 Wh kg−1 at 0.3 A g−1. Meanwhile, it can maintain an energy density of 90 Wh kg−1 at a high power density of 6.4 kW kg−1 (based on the cathode and 200% Zn anode), making it a promising candidate for high-performance, low-cost, safe, and environment-friendly energy-storage devices.
987 citations
727 citations
TL;DR: A microwave approach is developed to rapidly synthesize ultralong zinc pyrovanadate nanowires with a porous crystal framework with significantly improved electrochemical performance when used as intercalation cathode for aqueous zinc-ion battery.
Abstract: In this work, a microwave approach is developed to rapidly synthesize ultralong zinc pyrovanadate (Zn3 V2 O7 (OH)2 ·2H2 O, ZVO) nanowires with a porous crystal framework. It is shown that our synthesis strategy can easily be extended to fabricate other metal pyrovanadate compounds. The zinc pyrovanadate nanowires show significantly improved electrochemical performance when used as intercalation cathode for aqueous zinc-ion battery. Specifically, the ZVO cathode delivers high capacities of 213 and 76 mA h g-1 at current densities of 50 and 3000 mA g-1 , respectively. Furthermore, the Zn//ZVO cells show good cycling stability up to 300 cycles. The estimated energy density of this Zn cell is ≈214Wh kg-1 , which is much higher than commercial lead-acid batteries. Significant insight into the Zn-storage mechanism in the pyrovanadate cathodes is presented using multiple analytical methods. In addition, it is shown that our prototype device can power a 1.5 V temperature sensor for at least 24 h.
714 citations
TL;DR: A layered calcium vanadium oxide bronze as the cathode material for aqueous Zn batteries is reported, demonstrating that the calcium-based bronze structure can deliver a high capacity, good rate capability, and very long cycling life.
Abstract: Cost-effective aqueous rechargeable batteries are attractive alternatives to non-aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc-ion batteries (ZIBs), based on Zn2+ intercalation chemistry, stand out as they can employ high-capacity Zn metal as the anode material. Herein, we report a layered calcium vanadium oxide bronze as the cathode material for aqueous Zn batteries. For the storage of the Zn2+ ions in the aqueous electrolyte, we demonstrate that the calcium-based bronze structure can deliver a high capacity of 340 mA h g-1 at 0.2 C, good rate capability, and very long cycling life (96 % retention after 3000 cycles at 80 C). Further, we investigate the Zn2+ storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 W h kg-1 at a power density of 53.4 W kg-1 .
695 citations
TL;DR: Batteries using quinone cathodes and metal anodes in aqueous electrolyte are reliable approaches for mass energy storage and an electrostatic potential computing method is developed to demonstrate that carbonyl groups are active centers of electrochemistry.
Abstract: Quinones, which are ubiquitous in nature, can act as sustainable and green electrode materials but face dissolution in organic electrolytes, resulting in fast fading of capacity and short cycle life. We report that quinone electrodes, especially calix[4]quinone (C4Q) in rechargeable metal zinc batteries coupled with a cation-selective membrane using an aqueous electrolyte, exhibit a high capacity of 335 mA h g-1 with an energy efficiency of 93% at 20 mA g-1 and a long life of 1000 cycles with a capacity retention of 87% at 500 mA g-1. The pouch zinc batteries with a respective depth of discharge of 89% (C4Q) and 49% (zinc anode) can deliver an energy density of 220 Wh kg-1 by mass of both a C4Q cathode and a theoretical Zn anode. We also develop an electrostatic potential computing method to demonstrate that carbonyl groups are active centers of electrochemistry. Moreover, the structural evolution and dissolution behavior of active materials during discharge and charge processes are investigated by operando spectral techniques such as IR, Raman, and ultraviolet-visible spectroscopies. Our results show that batteries using quinone cathodes and metal anodes in aqueous electrolyte are reliable approaches for mass energy storage.
623 citations
TL;DR: It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.
Abstract: Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the UVA and UVB region of spectra due to wide bandgap. Impact of zinc oxide on biological functions depends on its morphology, particle size, exposure time, concentration, pH, and biocompatibility. They are more effective against microorganisms such as Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Sarcina lutea, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Pseudomonas vulgaris, Candida albicans, and Aspergillus niger. Mechanism of action has been ascribed to the activation of zinc oxide nanoparticles by light, which penetrate the bacterial cell wall via diffusion. It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.
600 citations
14 May 2018
515 citations
TL;DR: In this article, reversible intercalation of up to two Zn2+ ions in layered V3O7·H2O was investigated, and the results showed that the intercalated ions exhibited very high capacity and power (375 mA h g−1 at a 1C rate, and 275 m A h g −1 at an 8C rate) compared to a very low capacity and slow rate capabilities in a nonaqueous medium.
Abstract: Zinc ion batteries using metallic zinc as the negative electrode have gained considerable interest for electrochemical energy storage, whose development is crucial for the adoption of renewable energy technologies, as zinc has a very high volumetric capacity (5845 mA h cm−3), is inexpensive and compatible with aqueous electrolytes. However, the divalent charge of zinc ions, which restricts the choice of host material due to hindered solid-state diffusion, can also pose a problem for interfacial charge transfer. Here, we report our findings on reversible intercalation of up to two Zn2+ ions in layered V3O7·H2O. This material exhibits very high capacity and power (375 mA h g−1 at a 1C rate, and 275 mA h g−1 at an 8C rate) in an aqueous electrolyte compared to a very low capacity and slow rate capabilities in a nonaqueous medium. Operando XRD studies, together with impedance analysis, reveal solid solution behavior associated with Zn2+-ion diffusion within a water monolayer in the interlayer gap in both systems, but very sluggish interfacial charge transfer in the nonaqueous electrolyte. This points to desolvation at the interface as a major factor in dictating the kinetics. Temperature dependent impedance studies show high activation energies associated with the nonaqueous charge transfer process, identifying the origin of poor electrochemical performance.
512 citations
TL;DR: In this article, zinc vacancy defects are successfully introduced into zinc sulfide (ZnS) via adding sodium sulfide as sulfur source during the hydrothermal reaction, and the defective ZnS with different amount of zinc vacancies were employed as catalysts for the examination of vacancy-dependent catalytic activity toward photocatalytic hydrogen evolution under visible light irradiation.
Abstract: Zinc sulfide is a superior photocatalyst for H 2 evolution, whereas the wide bandgap restricts its performance to only UV region. In this work, zinc vacancy (V Zn ) defects are successfully introduced into ZnS via adding sodium sulfide as sulfur source during the hydrothermal reaction. The defective ZnS with different amount of zinc vacancies were employed as catalysts for the examination of vacancy-dependent catalytic activity toward photocatalytic hydrogen evolution under visible light irradiation. Fluorescence emission spectra and XPS results confirm that existence of abundant zinc vacancies on ZnS. These zinc vacancies exhibit remarkable effects on modifying the electronic structure of ZnS as shown in UV–visible absorption spectra and Mott–Schottky plots. Zinc vacancies can raise valence band (VB) position that weaken the oxidative capacity of the holes to protect Zn-deficient ZnS from photocorrsion. And electrochemical and photo-electrochemical experiments also demonstrate that the charge separation and the electrons transfer are more efficient with the introduction of the Zn vacancies in ZnS. The zinc-deficient ZnS-2.5 with optimum amount of Zn vacancies shows superior photocatalytic activity for H 2 evolution that reaches 337.71 ± 3.72 μmol h −1 g −1 under visible-light irradiation and also exhibits a much higher photostability. The intrinsic modify by self-defects might be a potential strategy for design novel photocatalysts with photocorrosion stability and visible-light activity in photocatalysis proton reduction.
TL;DR: In this paper, the authors developed various kinds of potassium vanadates (K2V8O21, K0.25V2O5, K2V6O16·1) as cathodes for aqueous ZIBs.
TL;DR: In this article, an Fe, Cu-coordinated ZIF-derived carbon framework (Cu@Fe-N-C) with a well-defined morphology of truncated rhombic dodecahedron is facilely prepared by introducing Fe2+ and Cu2+ during the growth of ZIF8, followed by pyrolysis.
Abstract: Zeolitic imidazole frameworks (ZIFs) offer rich platforms for rational design and construction of high-performance nonprecious-metal oxygen reduction reaction (ORR) catalysts owing to their flexibility, hierarchical porous structures, and high surface area. Herein, an Fe, Cu-coordinated ZIF-derived carbon framework (Cu@Fe-N-C) with a well-defined morphology of truncated rhombic dodecahedron is facilely prepared by introducing Fe2+ and Cu2+ during the growth of ZIF-8, followed by pyrolysis. The obtained Cu@Fe-N-C, with bimetallic active sites, large surface area, high nitrogen doping level, and conductive carbon frameworks, exhibits excellent ORR performance. It displays 50 mV higher half-wave potential (0.892 V) than that of Pt catalysts in an alkaline medium and comparable performance to Pt catalysts in an acidic medium. In addition, it also has excellent durability and methanol resistance ability in both acidic and alkaline solutions, which makes it one of the best Pt-free catalysts reported to date for ORR. Impressively, when being employed as a cathode catalyst in zinc–air batteries, Cu@Fe-N-C presents a higher peak power density of 92 mW cm−2 than that of Pt/C (74 mW cm−2) as well as excellent durability.
TL;DR: This study synthesized a sulfo-self-doped PANI cathode by a facile electrochemical copolymerization process and opens a door for the use of conducting polymers as cathode materials for high-performance rechargeable zinc batteries.
Abstract: Rechargeable aqueous zinc batteries are promising energy-storage systems for grid applications. Highly conductive polyaniline (PANI) is a potential cathode, but it tends to deactivate in electrolytes with low acidity (i.e. pH >1) owing to deprotonation of the polymer. In this study, we synthesized a sulfo-self-doped PANI electrode by a facile electrochemical copolymerization process. The -SO3 - self-dopant functions as an internal proton reservoir to ensure a highly acidic local environment and facilitate the redox process in the weakly acidic ZnSO4 electrolyte. In a full zinc cell, the self-doped PANI cathode provided a high capacity of 180 mAh g-1 , excellent rate performance of 70 % capacity retention with a 50-fold current-density increase, and a long cycle life of over 2000 cycles with coulombic efficiency close to 100 %. Our study opens a door for the use of conducting polymers as cathode materials for high-performance rechargeable zinc batteries.
TL;DR: A low-cost rechargeable aqueous Zn-V2O5 cell with 3 M ZnSO4 electrolyte that demonstrates high zinc storage capability is reported that is investigated.
TL;DR: In this paper, the authors present an extensive overview of electrolytes for rechargeable zinc batteries in relation to the anode issues which are closely affected by the electrolyte nature, including aqueous electrolytes, from alkaline to acidic pH, and non-aqueous systems including polymeric and room temperature ionic liquids.
Abstract: The revived interest and research on the development of novel energy storage systems with exceptional inherent safety, environmentally benign and low cost for integration in large scale electricity grid and electric vehicles is now driven by the global energy policies. Within various technical challenges yet to be resolved and despite extensive studies, the low cycle life of the zinc anode is still hindering the implementation of rechargeable zinc batteries at industrial scale. This review presents an extensive overview of electrolytes for rechargeable zinc batteries in relation to the anode issues which are closely affected by the electrolyte nature. Widely studied aqueous electrolytes, from alkaline to acidic pH, as well as non-aqueous systems including polymeric and room temperature ionic liquids are reported. References from early rechargeable Zn-air research to recent results on novel Zn hybrid systems have been analyzed. The ambition is to identify the challenges of the electrolyte system and to compile the proposed improvements and solutions. Ultimately, all the technologies based on zinc, including the more recently proposed novel zinc hybrid batteries combining the strong points of lithium-ion, redox-flow and metal-air systems, can benefit from this compilation in order to improve secondary zinc based batteries performance.
TL;DR: This Minireview first clarifies the formation and growth principles of zinc dendrites, then the research and development of methods to solve the problem of zinc Dendrites are reviewed, including ways to suppress the further formation androwth of dendrite as far as possible, to minimize the adverse effects of dendsrite.
Abstract: Zinc deposition and dissolution is a significant process in zinc-based batteries. During this process, the formation of zinc dendrites is pervasive, which leads to the loss of efficiency and capacity of batteries. The continually growing dendrites will finally pierce the separator and cause the batteries to short circuit. Thus, employing effective methods to inhibit the formation and growth of zinc dendrites is vital for the practical application of zinc-based batteries. This Minireview first clarifies the formation and growth principles of zinc dendrites. Then, the research and development of methods to solve the problem of zinc dendrites are reviewed, including ways to suppress the further formation and growth of dendrites as far as possible, to minimize the adverse effects of dendrites, along with ways to produce dendrite-free deposition processes. The mechanisms, advantages, drawbacks, and perspectives of these methods are illustrated. Thus, this overview of these methods will aid understanding of the formation process of zinc dendrites and provide an extensive, comprehensive, and professional reference to resolve the problem of zinc dendrites completely.
TL;DR: It can be concluded that ZnO NPs (levels used in the study) could effectively reduce the toxicity and concentration of Cd in wheat whereas increase the Zn concentration in wheat.
TL;DR: In this article, a new cathode material for neutral aqueous rechargeable rechargeable zinc battery was proposed, which is a new manganese oxide cathode with average Mn valence state lower than four for rechargeable Zn-birnessite.
TL;DR: In this paper, a zinc-ion micro-supercapacitor (ZmSC) is constructed by integrating a battery-type zinc micro-anode and a capacitor-type carbon nanotube micro-cathode.
Abstract: To achieve high energy and power density simultaneously in miniaturized electronic devices, a zinc-ion micro-supercapacitor (ZmSC) is constructed for the first time by integrating a battery-type zinc micro-anode and a capacitor-type carbon nanotube micro-cathode. In the meantime, an electroplating method is developed to in situ replenish the zinc anode when needed without destroying the configuration of the ZmSC, in which the micro-cathode, micro-anode and electrolyte of the ZmSC function as the working electrode, counter electrode and plating solution in the plating process, respectively. This strategy effectively avoids the irreversible consumption of the zinc anode and the fading of the capacitance and cycle life. As a result, the prepared ZmSC exhibits an excellent electrochemical performance, including a high area capacitance of 83.2 mF cm−2 at 1 mA cm−2, a high energy density of 29.6 μW h cm−2 and a high power density of 8 mW cm−2. After 6000 cycles, the ZmSC shows about 87.4% retention (60.9 mF cm−2) of its initial area capacitance at 5 mA cm−2. Furthermore, a higher capacitance (76 mF cm−2) and a longer cycling life are obtained after re-plating the zinc anode. This method features a simple configuration and easy operation, and holds great promise for use in other long cycle life zinc-based microdevices.
TL;DR: Aqueous hybrid Na-Zn batteries are designed by using a carbon-coated Zn (Zn@C) anode, 8 M NaClO4 + 0.4 M Zn(CF3SO3)2 concentrated electrolyte coupled with NASICON-structured cathodes and exhibit extraordinary performance including high voltage, high energy density, and excellent cycling stability of 1000 cycles.
Abstract: Aqueous batteries are promising energy storage systems but are hindered by the limited selection of anodes and narrow electrochemical window to achieve satisfactory cyclability and decent energy density. Here, we design aqueous hybrid Na–Zn batteries by using a carbon-coated Zn (Zn@C) anode, 8 M NaClO4 + 0.4 M Zn(CF3SO3)2 concentrated electrolyte coupled with NASICON-structured cathodes. The Zn@C anode achieves stable Zn stripping/plating and improved kinetics without Zn dendrite formation due to the porous carbon film facilitating homogeneous current distribution and Zn deposition. Furthermore, the concentrated electrolyte offers a large electrochemical window (∼2.5 V) and permits stable cycling of cathodes. As a result, the hybrid batteries exhibit extraordinary performance including high voltage, high energy density (100–150 Wh kg–1 for half battery and 71 Wh kg–1 for full battery), and excellent cycling stability of 1000 cycles.
TL;DR: To gain insights into the dual action of zinc, as either an antioxidant or a prooxidant, and the conditions under which each role is performed, the oxidative stresses that occur in zinc deficiency and zinc overload in conjunction with the intracellular regulation of free zinc are summarized.
Abstract: Zinc is recognized as an essential trace metal required for human health; its deficiency is strongly associated with neuronal and immune system defects. Although zinc is a redox-inert metal, it functions as an antioxidant through the catalytic action of copper/zinc-superoxide dismutase, stabilization of membrane structure, protection of the protein sulfhydryl groups, and upregulation of the expression of metallothionein, which possesses a metal-binding capacity and also exhibits antioxidant functions. In addition, zinc suppresses anti-inflammatory responses that would otherwise augment oxidative stress. The actions of zinc are not straightforward owing to its numerous roles in biological systems. It has been shown that zinc deficiency and zinc excess cause cellular oxidative stress. To gain insights into the dual action of zinc, as either an antioxidant or a prooxidant, and the conditions under which each role is performed, the oxidative stresses that occur in zinc deficiency and zinc overload in conjunction with the intracellular regulation of free zinc are summarized. Additionally, the regulatory role of zinc in mitochondrial homeostasis and its impact on oxidative stress are briefly addressed.
TL;DR: Zinc-based hybrid flow batteries are one of the most promising systems for medium-to large-scale energy storage applications, with particular advantages in terms of cost, cell voltage and energy density as mentioned in this paper.
TL;DR: Porous ternary metal sulfide integrated electrode materials with abundant electroactive sites and redox reactions are very promising for supercapacitors and thus as-synthesized Zn-Co-S/NF has great potential for practical applications.
Abstract: Porous ternary metal sulfide integrated electrode materials with abundant electroactive sites and redox reactions are very promising for supercapacitors. Herein, a porous zinc cobalt sulfide nanosheet array on Ni foam (Zn-Co-S/NF) was constructed by facile growth of 2D bimetallic zinc/cobalt-based metal-organic framework (Zn/Co-MOF) nanosheets with leaf-like morphology on NF, followed by additional sulfurization. The Zn-Co-S/NF nanosheet array acted directly as a supercapacitor electrode showing much better electrochemical performance (2354.3 F g-1 and 88.6 % retention over 1000 cycles) when compared with zinc cobalt sulfide powder (355.3 F g-1 and 75.8 % retention over 1000 cycles), which originates from good electrical conductivity and mechanical stability, abundant electroactive sites, and facilitated transportation of electrons and electrolyte ions due to the unique nanosheet array structure. An asymmetric supercapacitor (ASC) device assembled from Zn-Co-S/NF and activated carbon electrodes can deliver a highest energy density of 31.9 Wh kg-1 and a maximum power density of 8.5 kW kg-1 . Most importantly, this ASC also shows good cycling stability (71.0 % retention over 10000 cycles). Furthermore, a red LED can be powered by two connected ASCs, and thus as-synthesized Zn-Co-S/NF has great potential for practical applications.
TL;DR: There is a great interest in nano-zinc as improving the knowledge about individual forms of zinc and their uptake and assimilation within higher plants may be the first step towards a wider involvement of zinc nanoparticles into agriculture.
TL;DR: In this paper, the effect of copper doping on crystal structure of ZnO nanoparticles was investigated and the optical band gap of pure and copper-doped ZnOs was calculated from diffuse reflectance spectroscopy (DRS) spectra and was found to decrease from 3.13
Abstract: Pure and copper-doped zinc oxide nanoparticles (NPs) have been synthesized via chemical co-precipitation method where hydrazine is used as reducing agent and aqueous extract of Euphorbia milii plant as capping agent. Main objectives of the reported work are to investigate the effect of copper doping on crystal structure of ZnO nanoparticles; to study the effect of copper doping on optical band gap of ZnO nanoparticles and photoluminescence (PL) study of pure and copper-doped ZnO nanoparticles. To achieve the aforementioned objectives, XRD and SEM tests were performed for the identification and confirmation of crystal structure and morphology of the prepared samples. From XRD data the average grain size for pure ZnO was observed to be 24.62 nm which was first decreased to 18.95 nm for 5 wt% Cu-doped sample and then it was found to increase up to 37.80 nm as the Cu doping was increased to 7 wt%. Optical band gap of pure and Cu-doped ZnO nanoparticles was calculated from diffuse reflectance spectroscopy (DRS) spectra and was found to decrease from 3.13 eV to 2.94 eV as the amount of Cu increases up to 7 wt%. In photoluminescence study, PL technique was used and enhanced visible spectrum was observed. For further characterization FT-IR and EDX tests were also carried out.
TL;DR: In this article, an interesting electrochemically induced phase transition from monoclinic VO2 to bilayered V2O5·nH2O was demonstrated, which shows a significantly enlarged interlayer spacing, a reduced structural order, and an excellent structural stability in the following cycling.
Abstract: Aqueous zinc ion batteries have recently attracted increasing attention due to their high safety, low cost, and high volumetric energy density, but their development is also known to be severely impeded by the shortage of suitable cathode materials that show promising cycling capabilities. Herein we demonstrate an interesting electrochemically induced phase transition from monoclinic VO2 to bilayered V2O5·nH2O during the initial Zn2+ intake/removal, which shows a significantly enlarged interlayer spacing, a reduced structural order, and an excellent structural stability in the following cycling. This open and stable lamellar architecture enables an impressive battery performance: a capacity of 274 mA h g−1, a specific energy density of 271.8 W h kg−1, and an ultra-long lifespan (capacity retention of 79% over 10 000 cycles), which is superior to that of most reported vanadium oxide-based zinc ion batteries.
TL;DR: In this paper, a green process was used to synthesize biocompatible ZnO nanoparticles from the zinc nitrate via green process using leaf extracts of the Costus pictus D.Don medicinal plant.
Abstract: In this work we aim to synthesize biocompatible ZnO nanoparticles from the zinc nitrate via green process using leaf extracts of the Costus pictus D. Don medicinal plant. FTIR studies confirm the presence of biomolecules and metal oxides. X-ray diffraction (XRD) structural analysis reveals the formation of pure hexagonal phase structures of ZnO nanoparticles. The surface morphologies of ZnO nanoparticles observed under a scanning electron microscope (SEM) suggest that most ZnO crystallites are hexagonal. EDX analysis confirms the presence of primarily zinc and oxygen. TEM images show that biosynthesized zinc oxide nanoparticles are hexagonal and spherical. The plausible formation mechanisms of zinc oxide nanoparticles are also predicted. The biosynthesized zinc oxide nanoparticles exhibit strong antimicrobial behavior against bacterial and fungal species when employing the agar diffusion method. Synthesized ZnO nanoparticles exhibit anticancer activity against Daltons lymphoma ascites (DLA) cells as well as antimicrobial activity against some bacterial and fungal strains.