Zn Foil Substrate Research Articles

A colloidal aqueous electrolyte modulated by oleic acid for durable zinc metal anode

Continuous dendrites growth, as well as corrosion and side reactions of Zn metal anode seriously hinder the development of aqueous zinc ion batteries. To address these issues, oleic acid (OA) is dispersed into a 2 M ZnSO4 solution to form a novel colloidal Zn-ion electrolyte. The non-soluble OA surfactant doesn’t coordinate with Zn2+ and the water solvent. Instead, it works as a “temporary electrolyte additive” during initial stage of battery processing. After, the OA additive is bonded to Zn metal forming an OA adsorption layer on the anode surface. This hydrophobic OA adsorption layer can not only regulate Zn deposition with parallel orientation of the Zn (002) plane to the Zn foil substrate leading to a flat Zn metal anode, but also isolate direct contact of water with Zn thus inhibiting the harmful side reactions on the Zn anode. Consequently, this colloidal electrolyte enables highly reversible Zn deposition with Coulombic efficiency of 99.63 % and cycle life over 3340 cycles. This strategy of in-situ facet engineering and interface modification of Zn metal anode using colloidal electrolyte presents a new perspective toward design of high-performance aqueous zinc ion batteries.

Development of Dual-Nanoarchitecture Photoanodes Based on Microwave-Assisted ZnS(en)0.5 Nanoplates for Photoelectrochemical Hydrogen Generation

In this study, a microwave-assisted (MW) synthesis approach is used to develop an inorganic–organic ZnS(en)0.5 nanoplate (NP) on a Zn foil substrate. Morphological studies revealed that the growth of the ZnS(en)0.5 NP on Zn foil increased with prolonged MW irradiation time. Additionally, X-ray diffraction analysis, fourier transform infrared spectroscopy, and transmission electron microscopy unveiled the structural properties of the inorganic–organic hybrid ZnS(en)0.5 NP electrode to investigate the morphological evolution and the growth mechanism. Furthermore, the fabricated inorganic–organic ZnS(en)0.5 NP was exposed to Cd2+-ion exchange at different temperatures (140, 160, and 180 °C for 6 h) to improve its light absorption and photoelectrochemical properties. The Zn1–xCdxS porous nanoplate (PNP)/ZnO nanorod (NR)160 photoanode (160 °C for 6 h) exhibited a high photocurrent density of 4.81 mA·cm–2 at 0.5 V vs RHE. The optimized photoanode also yielded a hydrogen evolution rate of 89.76 μmol·cm–2 under 3 h of solar light illumination. Thus, the formation of the Zn1–xCdxS porous structure and the growth of the ZnO NR during Cd2+-ion exchange enhanced the photocurrent density and, consequently, prolonged the recombination lifespan of the Zn1–xCdxS PNP/ZnO NR160 photoanode.

Solid-Solution-Based Metal Coating Enables Highly Reversible, Dendrite-Free Aluminum Anode

Aluminum-ion batteries have attracted great interest in the grid-scale energy storage field due to their good safety, low cost and the high abundance of Al. However, Al anodes suffer from severe dendrite growth, especially at high deposition rates. Here, we report a simple strategy for constructing a highly reversible, dendrite-free, Al-based anode through directly introducing a solid-solution-based metal coating to a Zn foil substrate. Compared with Cu foil substrates and bare Al, a Zn foil substrate shows a lower nucleation barrier of Al deposition due to the intrinsic, definite solubility between Al and Zn. During Al deposition, a thin, solid-solution alloy phase is first formed on the surface of the Zn foil substrate and then guides the parallel growth of flake-like Al on Zn substrate. The well-designed, Zn-coated Al (Zn@Al) anode can effectively inhibit dendrite growth and alleviate the corrosion of the Al anode. The fabricated Zn@Al–graphite battery exhibits a high specific capacity of 80 mAh·g−1 and an ultra-long lifespan over 10,000 cycles at a high current density of 20 A·g−1 in low-cost molten salt electrolyte. This work opens a new avenue for the development of stable Al anodes and can provide insights for other metal anode protection.

Fabrication, characterization and photoelectrochemical properties of CdS/CdSe nanofilm co-sensitized ZnO nanorod arrays on Zn foil substrate

The photoelectrochemical (PEC) performance of ZnO is restricted by its low light absorption ability and high recombination rate of photogenerated carriers. In order to overcome these drawbacks, ZnO/CdS/CdSe heterostructures are prepared on Zn foil substrate using facile three-step methods containing hydrothermal growth, successive ionic layer adsorption reaction (SILAR) and modified chemical bath deposition (CBD). The effects of process parameters containing the number of SILAR cycles of CdS, sensitization sequence of CdS and CdSe, and precursors of CdSe on PEC performance of ZnO/CdS/CdSe heterostructures, and ZnO NRAs on PEC performance of CdS/CdSe co-sensitizer have been scrutinized. Through CdS and CdSe co-sensitization, a layer of CdS/CdSe nanofilm is conformally deposited on ZnO nanorod arrays (NRAs) observed by transmission electron microscopy (TEM). Both the visible-light absorption ability and separation efficiency of photogenerated carriers of ZnO NRAs are significantly enhanced evidenced by UV–vis diffuse reflectance absorption spectra, photoluminescence (PL) spectra and electrochemical impedance spectra. Due to the synergistic effect of ZnO NRAs and CdS/CdSe co-sensitizer, the ZnO/CdS/CdSe heterostructures with five SILAR cycles and one modified CBD cycle (ZnO-CdS5-CdSe) show efficient PEC properties with photocurrent density of 6.244 mA/cm2 at −0.2 V vs Ag/AgCl under light illumination of 100 mW/cm2, which are 57.28 and 4.73 times higher than those of pristine ZnO NRAs and CdS/CdSe clusters, respectively. Moreover, the photoconversion efficiency and incident photon to current conversion efficiency (IPCE) of the ZnO-CdS5-CdSe photoanode reach 4.381% and 80.92%, respectively. The heterostructures based on Zn foil substrate in this study can be a promising candidate for practical PEC application and other applications such as photocatalytic degradation and solar cell due to its low manufacturing cost, large-scale production and efficient PEC ability.

Architecting a Stable High-Energy Aqueous Al-Ion Battery.

Aqueous Al-ion batteries (AAIBs) are the subject of great interest due to the inherent safety and high theoretical capacity of aluminum. The high abundancy and easy accessibility of aluminum raw materials further make AAIBs appealing for grid-scale energy storage. However, the passivating oxide film formation and hydrogen side reactions at the aluminum anode as well as limited availability of the cathode lead to low discharge voltage and poor cycling stability. Here, we proposed a new AAIB system consisting of an AlxMnO2 cathode, a zinc substrate-supported Zn-Al alloy anode, and an Al(OTF)3 aqueous electrolyte. Through the in situ electrochemical activation of MnO, the cathode was synthesized to incorporate a two-electron reaction, thus enabling its high theoretical capacity. The anode was realized by a simple deposition process of Al3+ onto Zn foil substrate. The featured alloy interface layer can effectively alleviate the passivation and suppress the dendrite growth, ensuring ultralong-term stable aluminum stripping/plating. The architected cell delivers a record-high discharge voltage plateau near 1.6 V and specific capacity of 460 mAh g-1 for over 80 cycles. This work provides new opportunities for the development of high-performance and low-cost AAIBs for practical applications.

Enhanced photoelectrochemical performance based on conformal and uniform ZnO/ZnSe/CdSe heterostructures on Zn foil substrate

The erosion issue of ZnO nanorod arrays (NRAs) film is the major obstacle in surface sensitization of ZnO NRAs grown on Zn foil substrate for photoelectrochemical (PEC) applications. In this paper, PEC performance of ZnO NRAs grown on Zn foil substrate was greatly enhanced by coating ZnSe and CdSe on the surface of ZnO NRAs. Dense ZnO NRAs were in-situ grown on seed-free Zn foil substrate in a NH3·H2O and NaOH hydrothermal system. ZnSe/CdSe co-sensitized ZnO heterostructures were then successfully synthesized using ZnO NRAs as precursors by two successive in-situ ion exchanges without damaging Zn foil and ZnO NRAs film. To obtain optimal photoconversion efficiency, anion exchange time and temperature were optimized. ZnO/ZnSe/CdSe heterostructures with optimized structure were shown as a layer of compact ZnSe/CdSe nanofilm conformally and uniformly coated on ZnO NRAs, which leads to efficient separation of photogenerated carriers, significant enhancement in visible-light absorption, and excellent PEC performance with photocurrent density of 3.008 mA/cm2 (−0.2 V vs. Ag/AgCl) and photoconversion efficiency of 1.99% (0.418 V vs. RHE in polysulfide electrolyte solution), 27.55 and 40.61 times higher than those of ZnO NRAs, respectively.

ZnO/ZnS heterostructures grown on Zn foil substrate by hydrothermal method for photoelectrochemical water splitting

ZnO nanorod arrays (NRAs) grown on the Zn foil substrate in the dual alkaline solution by hydrothermal method were first successfully utilized for photoelectrochemical (PEC) water splitting. ZnO NRAs were sufficiently covered on the Zn foil substrate via the reasonable match of the pH value, reaction temperature and reaction time through intensive experimental works. To enhance PEC performance, ZnS was coated on the surfaces of ZnO NRAs by ion exchange. The morphological, structural, optical and PEC characteristics of as-grown ZnO NRAs and ZnO/ZnS heterostructures were investigated. Compared with the pristine smooth and hexagonal ZnO NRAs, the surfaces of ZnO/ZnS heterostructures become rough and rounded in shape. Through the sulfidation treatment, some ZnO/ZnS heterostructures with a diameter of no more than 60 nm break and fade away, leading to a decrease in number density of ZnO/ZnS heterostructures. The texture coefficients of (002) diffraction peaks of ZnO decrease from 2.32 to 2.158. ZnO/ZnS heterostructures exhibit efficient separation rate of electron-hole pairs and enhanced visible light absorption, and thus have higher photocurrent density and photoconversion efficiency. In the polysulfide electrolyte solution, ZnO/ZnS heterostructures show good stability.

A resistive switching memory device with a negative differential resistance at room temperature

In this study, large-area ZnO nanorod arrays covering a Zn foil substrate were produced by a low-cost and low temperature approach. In this approach, oxidation of zinc metal was achieved in a formamide/water mixture. Taking advantage of the product, a sandwiched structure, Ag/ZnO/Zn, was fabricated in which Ag acts as the top electrode, ZnO as the active layer and Zn foil as the bottom electrode. Resistive switching memory behavior (with an HRS/LRS resistance ratio of ∼10) along with a negative differential resistance effect (the largest slope being −3.85) was synchronously observed for this device at room temperature. This device opens up possibilities for multifunctional components in future electronic applications.

3D hyperbranched heterostructures of Ag nanocrystals-decorated ZnO nanopillars: controlled growth and characterization of the optical properties

Mechanistic formation of 3D hierarchical structure of silver-decorated ZnO nanopillars grown on Zn foilviaa hydrothermal route.

In Situ Fabrication of Novel Ag Dendrites Film by a Simple Replacement Reaction on Zn Foil Substrate

In this work, well-defined silver dendrites were fabricated by a simple electroless, template-free, and surfactant-free replacement reaction method using Zn foil and AgNO3 as the precursors. The products were studied by X-ray diffraction, scanning electron microscopy, transmitting electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy. The effect of the reaction time on the formation of Ag dendrites was investigated, which will open a new way to synthesize silver dendrites as electrodes applied in the field of solar cells and QLEDs. An oriented attachment-based aggregation model has been proposed to rationalize the formation of Ag dendrites.

Synthesis of semiconductor oxide nanosheets, nanotetrapods and nanoplane-suite like grown on metal foil using different method

ZnO production nanostructure using different method: first method, electrochemical deposition on Zn foil using 0.3 M zinc sulfate heptahydrate (ZnSO4·7H2O) and sulfuric acid aqueous solution at a current density of 30 and 35 mA/cm2 for deposition time 40 min at room temperature and second method, Zn foils were thermally oxidized in a conventional tube furnace at a temperature equal range of 700–900 °C in air for 5 h or less in static air to prepared semiconductor nanomaterials ZnO nanorods, nanotetrapods and nanoplane. The XRD diffraction of higher intensity peaks at (101) and (002) miller indices for two methods can be recognized to a hexagonal wurtzite structure unit cell. Surface morphology images with different magnifications which clearly shows that the whole Zn foil and rod substrate obtained ZnO nanosheets, nanotetrapods, nanorods and growth nanoplanes were also found. The length of these nanotetrapods and nanorods lies in the equal range of 1–1.5 µm with an average diameter of 80 nm. It was well known that ZnO nano crystal exhibited two emission peaks. One was located at about 365 nm wavelength (UV luminescence band), and the other peak position at 475 nm wavelength (green luminescence band).

Facile solution growth of vertically aligned ZnO nanorods sensitized with aqueous CdS and CdSe quantum dots for photovoltaic applications

Vertically aligned single crystalline ZnO nanorod arrays, approximately 3 μm in length and 50-450 nm in diameter are grown by a simple solution approach on a Zn foil substrate. CdS and CdSe colloidal quantum dots are assembled onto ZnO nanorods array using water-soluble nanocrystals capped as-synthesized with a short-chain bifuncional linker thioglycolic acid. The solar cells co-sensitized with both CdS and CdSe quantum dots demonstrate superior efficiency compared with the cells using only one type of quantum dots. A thin Al2O3 layer deposited prior to quantum dot anchoring successfully acts as a barrier inhibiting electron recombination at the Zn/ZnO/electrolyte interface, resulting in power conversion efficiency of approximately 1% with an improved fill factor of 0.55. The in situ growth of ZnO nanorod arrays in a solution containing CdSe quantum dots provides better contact between two materials resulting in enhanced open circuit voltage.

Hierarchical ZnO Micro‐/Nano‐Structure Film

ZnO micro-/nano-structure film composed of urchin-like hierarchical ZnO units with bamboo-like branches has been successfully constructed on Zn foil substrate by a simple one-step thermal evaporation process using a mixture of ZnS and graphite powder as a source. Field-emission scanning electron microscope (FE-SEM) observation demonstrates that different urchin-like ZnO structures are believed to originate from different Zn microshpere precursors.

Self-organized Zn/ZnO core-shelled hierarchical structures prepared by aqueous chemical growth

Self-assembled core-shelled hierarchical structures consisting of single-crystalline pyramid Zn microtip as a core, converted ZnO coating as the shell, and the grown ZnO nanowires as branches, have been prepared. Such ZnO hierarchical structures fabricated by a simple aqueous chemical growth method on Zn foil substrate are expected to be easily integrated into nanodevices. These self-organized structures are superior to both the random nanoarchitecture arrays formed in vapor system and the precipitated nanostructures suspended in the solution. Because of the easier transportation of electrons from the metallic core to ZnO branches, the self-assembled core-shelled hierarchical structures exhibit better field-emission characteristics.