Zn Powder Research Articles

Various CVD-grown ZnO nanostructures for nanodevices and interdisciplinary applications

This work presents a simple chemical vapour deposition (CVD) method to grow ZnO nanostructures. By annealing Zn powder under atmospheric pressure conditions, we collected nanocrystals with various morphologies, including rods, pencils, sheets, combs, tetrapods, and multilegs. Raman scattering study reveals that the samples are monophasic with a hexagonal structure, and fall into the P63mc space group. Depending on the morphology and crystal quality, their photoluminescence spectra have only a strong UV emission associated with the exciton radiative recombination, or both UV and defect-related visible emissions with their relative intensity ratio varying with the excitation power density. The obtained results prove that ZnO exhibits many novel nanostructures that can foster the development of next-generation optoelectronic nanodevices and new applications in biological and biomedical fields.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High‐Performance Aqueous Zinc‐Vanadium Batteries

AbstractA zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn–ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi‐functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high‐valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn−Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al‐containing cathode–electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra‐long cycle of 6000 h at 2 mA cm−2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS−KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm−2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Stabilizing zinc powder anodes via bifunctional MXene towards flexible zinc-ion batteries

Flexible zinc (Zn) batteries have gained considerable attention as wearable energy storage devices because of their inherent safety and high theoretical capacity. However, conventional Zn anodes suffer from dendrite growth, high rigidity, and poor cycling stability issues, hindering their practical application in flexible zinc-ion batteries. Herein, a dendrite-free and flexible Zn anode is designed using direct ink writing (DIW) printed MXene as a flexible and highly conductive current collector and MXene-wrapped Zn powder (ZnP) as the active material by carefully optimising the rheological properties of MXene-based dispersion. As a result, the synergistic effects of the MXene-based current collector and the MXene protective layer promoted dendrite-free Zn deposition and prevented side reactions, achieving an outstanding cycling performance that exceeded 130 h at a high depth of discharge of 30%. When paired with a Vanadium pentoxide (V2O5)-based cathode, the flexible full cell demonstrated stable electrochemical performance under mechanical deformation and can power electronic devices, presenting a promising pathway for the development of flexible zinc-ion batteries.

Electro-discharge deposition of zinc powder on 316L stainless steel: Synthesis, deposition rate, and characterization

This study investigated the potential of powder-mixed electrical discharge machining (PM-EDM) to deposit metallic powder, specifically zinc powder, on 316L stainless steel (316L SS). This study aimed to evaluate the effect of zinc (Zn) deposition on 316L SS for oil and gas application. Minitab 19 software was employed to design the experiments using screening DOE option and to analyse and model the results through screening response optimiser from Minitab 19 software. Surface morphology, microstructure and coating thickness were examined through field-emission scanning electron microscopy (FESEM) and scanning electron microscope (SEM). The results suggested an improvement in the coating thickness with an increase in powder concentration and discharge current. An average coating thickness of 91.47 μm was achieved in samples fabricated at 20 g/L powder concentration. X-ray diffraction analysis revealed the formation of hard carbides, such as Cr3C2 and TiC, on the PM-EDMed 316L SS surface. Further characterisation through energy-dispersive X-ray spectroscopy confirmed the deposition of both the tool electrode and Zn powder particles. The adhesion test confirmed that all specimens failed under 100% adhesive failure. The hydrophobicity analysis confirmed that the coated surfaces are hydrophobic. Significant improvement has been established for microhardness, wear resistance and corrosion performance. Screening results revealed that discharge current, pulse-on time, and powder concentration were the most significant parameters. The average predicted errors of 2.055%, 6.782%, and 2.396% for material deposition rate, tool wear rate, and surface roughness were achieved, respectively. These affirmed the excellent reproducibility of the model developed. This study presents a methodology for the formation of carbide- and oxide-based coatings specifically for oil and gas applications (flanges and connectors).

Fully Printed and Sweat-Activated Micro-Batteries with Lattice-Match Zn/MoS2 Anode for Long-Duration Wearables.

Aqueous zinc-ion batteries with superior operational safety have great promise to serve as wearable energy storage devices. However, the poor cycling stability and low output voltage limited their practical applications. Here, fully printable Zn/MoS2-MnO2 micro-batteries are developed and demonstrated significantly enhanced cycling stability with sweat activation. 2D MoS2 is utilized to enable lattice-matching with Zn powders to realize printed Zn anodes with desirable stability and promote electron/ion transfer. Interestingly, the mild acid epidermal sweat also contributed to eliminating the MnO2 cathode by-products and compensating for the hydrogel electrolytes' water loss. The Zn/MoS2-MnO2 micro-batteries achieve a high specific capacity of 318.9µAhcm-2 at the current density of 0.16mAcm-2, and an energy density of 424.6µWhcm-2, with remarkable cycle stability of ≈90% after 250 cycles. In-battery electrochromic display of capacity level and feasible electronics charging are demonstrated. The as-printed micro-batteries with innovative sweat activation would inspire the advances of sustainable power supply for wearables.

Improving bond strength and deposition efficiency of ceramic coatings via low pressure cold spraying: A study on hydroxyapatite coatings with Cu-Zn blends

This study presents Low Pressure Cold Spraying (LPCS) method for ceramic coatings, aimed at enhancing efficiency and elucidating bonding mechanisms. It focuses on the deposition of ceramic coatings using LPCS, with hydroxyapatite (HA) on 316L stainless steel (SS) as an illustrative example. Despite the advantages of LPCS, retaining HA particles has proven challenging, resulting in thin coatings (11.09 ± 2.56 μm) with low bonding strength (1.80 ± 0.19 MPa). To address this issue, a composite coating strategy was developed by blending 20 wt% Cu and Zn powder with 80 wt% HA. This approach significantly improved coating properties, achieving enhanced bonding strength (33.70 ± 1.13 MPa), deposition efficiency (27 %), and hardness (136.30 ± 2.45 HV) compared to pure Cu-Zn coatings. Numerical simulations were conducted to interpret these experimental results, indicating that blending metal with HA improves deposition efficiency, bonding strength, and hardness. In HA coatings, particles fragment into submicron grains and embed into the substrate through mechanical interlocking (MI), with shockwave-induced bonding strengthening subsequent layers. For Cu-Zn coatings, bonding occurs through MI and adiabatic shear instability (ASI). In HA-Cu-Zn coatings, high-velocity HA particles and Zn particles enhance bonding further through in-situ tamping.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High-Performance Aqueous Zinc-Vanadium Batteries.

A zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn-ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi-functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high-valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn-Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al-containing cathode-electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra-long cycle of 6000 h at 2 mA cm-2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS-KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm-2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Crystalline Texture Reengineering of Zinc Powder-Based Fibrous Anode for Remarkable Mechano-Electrochemical Stability.

The challenge of inadequate mechano-electrochemical stability in rechargeable fibrous Zn-ion batteries (FZIBs) has emerged as a critical challenge for their broad applications. Traditional rigid Zn wires struggle to maintain a stable electrochemical interface when subjected to external mechanical stress. To address this issue, a wet-spinning technique has been developed to fabricate Zn powder based fibrous anode, while carbon nanotubes (CNTs) introduced to enhance the spinnability of Zn powder dispersion. The followed annealing treatment has been conducted to reengineer the Zn crystalline texture with CNTs assisted surface tension regulation to redirect (002) crystallographic textural formation. The thus-derived annealed Zn@CNTs fiber demonstrates great mechano-electrochemical stability after a long-term bending and electrochemical process. The fabricated FZIB demonstrates a remarkable durability, surpassing 800h at 1mAcm-2 and 1mAhcm-2, with a marginal voltage hysteresis increase of 21.7mV even after 100 twisting cycles under 180 degree twisting angle. The assembled FZIB full cell displays an 88.6% capacity retention even after a long cycle of a series of bending, knotting, and straightening deformation. It has been also woven into a 200cm2 size textile to demonstrate its capability to integrate into smart textiles.

Oxygen-rich 3D hierarchical porous MXene prepared by Zn powder reduction for flexible supercapacitors

Ti3C2Tx MXene is highly compelling as an energy storage material, but 2D MXene sheets experience significant stacking due to hydrogen bonding and van der Waals forces. This blocks active sites and impedes fast electrolyte ion transport. The pseudocapacitance of MXene materials is highly reliant on their terminal groups. Therefore, an effective strategy was designed herein to prepare an oxygen-rich 3D hierarchical porous MXene (P-OR-Ti3C2Tx). First, Zn powder was used as a template to construct three-dimensional hierarchical porous structures that spanned the microporous, mesoporous, and macroporous scales. Second, Zn powder was used as a metal reducing agent in a reaction at 500 °C to eliminate most −F terminal groups on the MXene. Then, a subsequent acid washing step was used to introduce numerous −O terminal groups. The energy storage process of the prepared MXene was investigated by in situ Raman. More redox active sites (−O terminal groups) are exposed by the constructed oxygen-rich 3D hierarchical porous MXene structure, which also provides a shorter pathway for electrolyte ion transport. P-OR-Ti3C2Tx displays superb rate performance (88.19 % retention at 100Ag−1) and ultra-high capacitance (676.7F/g at 2 mV/s and 698.7Fg−1 at 1 Ag−1) when used as a supercapacitor electrode. Moreover, a symmetric flexible supercapacitor device prepared using P-OR-Ti3C2Tx and carbon cloth achieves a superb energy density of 32.8Whkg−1 at a power density of 236.5Wkg−1. This study offers insight into the design of MXenes that exhibit both high capacity and excellent rate performance.

(Invited) Recycling Zn for Rechargeable Zinc-Ion Batteries

Aqueous energy storage devices require highly reversible Zn electrodes, but this has been impeded by challenges including dendrite growth, low efficiency, hydrogen evolution, and metal corrosion. Here, we have successfully fabricated a reversible Zn powder electrode via engineering the growth of zinc crystals in different solvents from spent Zn foils. Theoretical calculations demonstrate that the adsorption energy gap of different solvents on the (002) or (100) facet of Zn metal varies and that a larger energy gap favors a higher orientation of Zn (002) plane. Highly oriented Zn (002) powder exhibits horizontal deposition, corrosion resistance, faster kinetics, and longer life under deep discharge (60%) in symmetric cells compared with less-oriented Zn. Under practical conditions including low N/P ratios (1–3), high-loading cathodes (10–18 mg cm−2), and lean electrolyte (5–9 μL mg−1), highly (002)-oriented Zn powder-based batteries and supercapacitors demonstrate large capacity (∼3 mAh cm−2) and energy/power density (108 Wh kg−1/2,317 W kg−1), holding promise for applications. And for the first time, we have also upcycled spent alkaline batteries into rechargeable Zn metal batteries through a simple thermal treatment of electrode waste. The regenerated Zn powder anode shows super-zincophilicity and low overpotentials even under fast rates (8 mA cm−2) and high depth-of-discharge (50 %), which can be ascribed to coating of hydroxyl-rich organic layer with abundant nucleation sites as well as high orientation of favorable (002) plane and induced horizontal plating behavior. The regenerated cathode composed of MnO2 and MnOOH manifests enhanced capacity in comparison to pristine ones. Under a low negative-to-positive capacity ratio of 3.8 and high loading of ~10 mg cm−2, the regenerated electrodes are paired to fabricate zinc metal batteries which demonstrate high energy and power densities (94 Wh kg−1, 1349 W kg−1), holding potential for practical applications. Given the sustainable, low-cost, environmental-friendly, and value-added features, the strategy proposed here will open a new pathway toward battery recycling/upcycling.

Stabilization of flake Zn powder anodes via designing functional additives in electrolytes for aqueous Zn ion batteries

Zn powder anodes have attracted much attention in aqueous Zn ion battery applications due to advantages such as low cost and processability. However, the high-activity Zn powder anode faces problems such as side reactions, hydrogen evolution, and dendrites, which limit the cycling stability of the cell. In this work, the high activity of Zn powder is weakened by introducing low-cost erythritol as a functional additive in the ZnSO4 electrolyte to improve the cycle life of the cell. Both theoretical calculations and empirical evidence demonstrate that the incorporation of erythritol alters the coordination sphere of Zn2+ and modifies the local molecular architecture of the electrolyte. This modification serves to diminish the reactivity of water molecules, thereby efficaciously suppressing dendrite formation and deleterious ancillary reactions on the zinc powder anode surfaces. Concurrently, erythritol functions as an interfacial cationic captor, enhancing reaction dynamics and facilitating the development of a favorable protective layer throughout the zinc plating/stripping process. Consequently, the symmetric cell paired with an erythritol-containing electrolyte manifests stable cycling performance for an extended duration of 850 h at a current density of 0.288 mA cm−2 and areal capacity of 0.144 mAh cm−2. Notably, it maintains a cycling life of 400 h even under intensified conditions (2.88 mA cm−2/1.44 mA h cm−2). Furthermore, the constructed Na2V6O16·3H2O full cell illustrated remarkable capacity retention of 155.8 mA h g−1 following 800 cycles at a high rate of 5 A g−1.

Preparation of active zinc oxide from zinc-containing dust and synergistic recovery process of valuable elements

Zinc-containing dust generated from the iron and steel industry is enriched with a large amount of heavy metal substances and rare elements, which is a hazardous waste and a secondary resource. In this study, a new process for the preparation of active zinc oxide and synergistic recovery of valuable elements using zinc-containing dust was proposed. Firstly, a fire process was used to make the valuable components such as Zn, Cd, K, Na, Pb, Bi, In and Sn secondary enriched in the zinc-rich dust. Then the leaching and recovery of K (99.74 %) and Na (98.12 %) were realized by alkaline washing method taking advantage of the solubility difference. Thermodynamic analysis showed that controlling the pH of the leaching system could realize the selective separation of the valuable components. The experimental results showed that the leaching rates of Zn and Cd reached 86.95 % and 92.28 %, respectively, under the optimal experimental conditions, while Pb, Sn, Bi and In were enriched in the neutral leaching slag. Cd sponge (70.3 %) was obtained after the neutral leach solution was treated by Zn powder replacement process. The purified zinc sulfate solution was used to prepare active zinc oxide (97.04 %) by direct precipitation at a molar ratio of CO32–/Zn2+ of 1.15 and a temperature of 50 °C. The average particle size of the product was 21.95 nm, which was in accordance with the industry standard. Neutral leaching slag realized Bi (91.5 %), Sn (71.01 %) and In (94.0 %) in high acid leaching process, and Pb was enriched in slag in the form of PbSO4. The high acid leach solution is hydrolyzed, extracted and replaced to obtain BiOCl, crude tin and crude indium. This process realizes the comprehensive recovery and high-value utilization of various valuable elements in zinc-containing dust sludge, and has significant environmental, economic and social benefits.

Microstructure, hardness, electrical, and thermal conductivity of SZCN solder reinforced with TiO2 and ZrO2 nanoparticles fabricated by powder metallurgy method

The microstructure and characterization of Sn–Zn–Cu–Ni (SZCN) solder alloy reinforced with TiO2 and ZrO2 nanoparticles (NPs) synthesized by powder metallurgy were investigated. Sn, Zn, Cu and Ni metallic powders were mixed mechanical by 10:1 ball to powder ratio with 300 rpm speed for 2 h. Then 0.5 wt% from nano ZrO2 or TiO2 was mixed by the same parameters with the mixed metal powder. The morphologies and microstructures development during the fabrication process was investigated by X-ray diffractometer (XRD), optical microscope (OM), and scanning electron microscope (SEM) with energy dispersive X-ray spectrometry (EDX). The results reveal an improved distribution of TiO2 or ZrO2 NPs in the SZCN matrix solder, which resulted in an improvement in its density. The analyses of microstructural demonstrated that the addition of TiO2 or ZrO2 NPs to SZCN solder results in the grain refinement of the β-Sn phase, besides the formation of Ni3Sn IMC with small size and uniform distribution. The microhardness was enhanced as a result of the addition of TiO2 or ZrO2 NPs. The experimental results showed that the SZCN-ZrO2 composite solder had the greatest hardness and stress exponent values due to its effectiveness in suppressing the growth of β-Sn grains and the pile-up of dislocations. Both the electrical and thermal conductivities were improved by incorporating TiO2 NPs compared to other solders.

Deeply Discharged, Quiescently Stable, and Long-Life Zn Anode by Spontaneous SEI Formation.

Zn ion batteries (ZIBs) are a promising candidate in safe and low-cost large-scale energy storage applications. However, significantly deteriorated cycling stability of Zn anode in high depth of charge or after long-term quiescence impedes the practical application of ZIBs. Aiming at the above issue, a spontaneous solid electrolyte interphase (SEI) formation of Zn4(OH)6SO4·xH2O (ZHS) on Zn powder is achieved in pure ZnSO4 electrolyte by facile and rational interface design. The stable and ultrathin ZHS SEI plays a crucial part in insulating water molecules and conducting Zn2+ ions, intrinsically suppressing the severe hydrogen evolution and dendrite formation on the Zn powder anode. The ZHS-Zn anode delivers a stable cycling at a high DOD of 50% for over 500h, as well as a lifespan of over 200h after 40-days of resting at a DOD of 25%. Benefiting from the high utilization of Zn anode, the energy density of the Zn-MnxV2O5 full cell is up to 118WhKg-1. This facile method can fabricate the ZHS-Zn anode as long as 1m, revealing its feasibility in large-scale production and commercialization.

Liquid Metal-Skinned Zn Powder Anodes Enabled by Capillary Suspension

Liquid Metal-Skinned Zn Powder Anodes Enabled by Capillary Suspension

Harnessing the Potential of Zn Powder Anodes: Innovations and Future Directions in Aqueous Zinc‐Ion Batteries

AbstractThe pursuit of alternative anode materials featuring inexpensive, efficient, and adaptable is shaping the future of rechargeable zinc‐ion batteries. The Zn powder anodes stand out among contenders due to their cost‐effectiveness, exceptional processability, and adjustability. However, their widespread use is hampered by significant challenges, including volume expansion and dendrite growth. To counter these issues, a gamut of optimization strategies for Zn powder anodes has been explored and developed. This review systematically encapsulates these research findings, offering a comprehensive understanding of various enhancement methods, such as three‐dimensional printing, in‐situ surface engineering, scalable electrostatic self‐assembly, and epoxy oligomer binding. These methodologies are discussed in detail in the context of their unique synthesis methods and underlying mechanisms. The paper concludes by outlining prospective research trajectories aimed at further optimizing the use of Zn powder anodes in aqueous zinc‐ion batteries, thereby illuminating potential avenues for future exploration and development.

Self-mixing anti-corrosive Zn-In powder composite anode with ultra-long lifespan for aqueous zinc-ion battery

Appropriate design of electrode structure and chemistry for Zn metal anode is important to the kinetics and electrochemical stability of Zn in aqueous batteries. Herein, In modified Zn powder electrode with carbon nanofibers as the stable electric conductive matrix provides an effective approach to simultaneously enhance reaction kinetics and inhibit H2 generation reactions. The designed Zn–In powder electrode presents self-mixing In distribution within the electrode during cycling thus enabling superior anti-corrasion and stable conductive network that significantly alters the Zn deposition behavior. Instant 3D Zn deposition with super-fast interfacial kinetics is achieved due to favorable Zn nucleation and growth as well as suppressed side reactions. Stable cycling of over 6300 h is achieved, which is 30-fold longer lifespan than Zn foil anode. Even at 5 mA cm−2, 5 mAh cm−2 (depth of discharge: 31.1%), Zn–In powder anode still presents stable cycling of over 500 h and low polarization voltage. Ultra-long cycle life of over 20,000 cycles can be achieved for full cells using Zn–In powder electrode paired with V2O5 cathode. Modified composite Zn powder electrode provides an effective and practical approach to address the electrochemical stability of Zn-based anodes in rechargeable cells.

Effects of MgO nanoparticle addition on the mechanical properties, degradation properties, antibacterial properties and in vitro and in vivo biological properties of 3D-printed Zn scaffolds

Bone tissue engineering is the main method for repairing large segment bone defects. In this study, a layer of bioactive MgO nanoparticles was wrapped on the surface of spherical Zn powders, which allowed the MgO nanoparticles to be incorporated into 3D-printed Zn matrix and improved the biodegradation and biocompatibility of the Zn matrix. The results showed that porous pure Zn scaffolds and Zn/MgO scaffolds with skeletal-gyroid (G) model structure were successfully prepared by selective laser melting (SLM). The average porosity of two porous scaffolds was 59.3 and 60.0%, respectively. The pores were uniformly distributed with an average pore size of 558.6–569.3 μm. MgO nanoparticles regulated the corrosion rate of scaffolds, resulting in a more uniform corrosion degradation behavior of the Zn/MgO scaffolds in simulated body fluid solution. The degradation ratio of Zn/MgO composite scaffolds in vivo was increased compared to pure Zn scaffolds, reaching 15.6% at 12 weeks. The yield strength (10.8 ± 2.4 MPa) of the Zn/MgO composite scaffold was comparable to that of cancellous bone, and the antimicrobial rate were higher than 99%. The Zn/MgO composite scaffolds could better guide bone tissue regeneration in rat cranial bone repair experiments (completely filling the scaffolds at 12 weeks). Therefore, porous Zn/MgO scaffolds with G-model structure prepared with SLM are a promising biodegradable bone tissue engineering scaffold.

Investigating the properties of a ZnSe-based solid solution at 2.0 GPa

In this work, ZnSe-based polycrystalline ceramics were successfully synthesized from Se and Zn powders in the range of 2.0 GPa and 900 °C–1400 °C by using the high-pressure and high-temperature (HPHT) method. From the acquired experimental results, it was revealed that the fabricated samples were composed of ZnSe with a sphalerite structural type. More specifically, the samples consisted of lamellar and granular grains, and the stomata of the samples showed a trend of first increasing and then decreasing as a function of the elevated temperature. In addition, the infrared transmittance of ZnSe ceramics in the 4 to 18-μm range increased and then decreased by increasing the temperature. When the temperature exceeded the value of 1000 °C, the internal zinc surplus and selenium deficiency of zinc selenide ceramics induced a decrease in the mechanical and optical properties of the ceramics. By optimizing the conditions of the experimental process, the ZnSe synthesized at 1300 °C exhibited better performance with a transmittance of 55%.

Study of The Effect of Calcination Temperature on the Phase Composition of ZnO Powder Synthesized via The Sol-Gel Method

This study investigated the effect of calcination temperature on the phase composition and crystal size of zinc oxide powders synthesised by the sol-gel method. Zn powder, HCl and NaOH were used as precursors in a multi-step process involving dissolution, titration, gel formation, leaching, drying and calcination at temperatures ranging from 300°C to 700°C for 2 hours. Rietveld analysis of X-ray diffraction (XRD) data using MAUD and Rietica software determined phase composition and crystal size. Initial analysis identified a single simonkolleite phase (Zn5(OH)8Cl2) prior to calcination, which disappeared at 500°C. Wurtzite (ZnO) appeared at 300°C, accompanied by secondary phases (NaCl and ZnCl2). The wurtzite content increased to 81.42 wt% at 700°C. Calcination temperature also influenced crystal size, which ranged from 27.34 nm to 110.61 nm for wurtzite at different temperatures. The results highlight the dynamic changes in phase composition and crystal size with different calcination temperatures, providing valuable insights into tailoring zinc oxide properties for various applications.