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Ti3C2Tx MXene, as a common two-dimensional material, has a wide range of applications in electrochemical energy storage. However, the surface forces of few-layer or monolayer Ti3C2Tx MXene lead to easy agglomeration, which hinders the demonstration of its performance due to the characteristics of layered materials. Herein, we report a facile method for preparing monolayer Ti3C2Tx MXene on nickel foam to achieve a self-supporting structure for supercapacitor electrodes under high electrostatic fields. Moreover, the specific capacitance varies with the deposition of different-concentration monolayer Ti3C2Tx MXene on nickel foam. As a result, Ti3C2Tx/NF has a high specific capacitance of 319 mF cm−2 at 2 mA cm−2 and an excellent long-term cycling stability of 94.4% after 7000 cycles. It was observed that the areal specific capacitance increases, whereas the mass specific capacitance decreases with the increasing loading mass. Attributable to the effect of the high electrostatic field, the self-supporting structure of the Ti3C2Tx/NF becomes denser as the concentration of the monolayer Ti3C2Tx MXene ink increases, ultimately affecting its electrochemical performance. This work provides a simple way to overcome the agglomeration problem of few-layer or monolayer MXene, then form a self-supporting electrode exhibiting excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

In this study, pure ZnO and Al-doped ZnO(AZO) thin films were coated onto a SiO2 wafer using the electrostatic spray deposition (ESD) process for acetone gas detection under laboratory conditions. Voltage levels were varied to determine the optimal conditions for producing thin films with the highest uniformity. The results indicate that the optimal coating voltage for achieving the highest uniformity of the coated films is 2.9 kV for ZnO and 2.6 kV for AZO. The thin films were produced under these optimal ESD conditions by adjusting the coating time, and gas sensors were fabricated by printing electrodes using a reverse offset process on top of the thin films. Analysis of the sensing response revealed that the AZO-coated gas sensor with a 200 s deposition exhibited the best acetone-sensing ability at 300 °C, with a maximum response of 13.41 at 10 ppm. Furthermore, the fabricated gas sensors effectively detected acetone gas even at a low concentration of 2 ppm, demonstrating high selectivity in comparison to other gases. [ABSTRACT FROM AUTHOR]

Electrostatic spray deposition was applied to prepare pH sensing with spinel ZnCO2O4 thin films based on the measurement of extended-gate field-effect transistors (EGFET). The influence of annealing temperatures on the characteristics of the prepared films was analyzed. The structural and morphological properties of the annealed ZnCo2O4 films were assessed by x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and contact angle measurement. The effect of the ZnCo2O4 annealing temperature on the characteristics of pH sensing for the prepared ZnCo2O4 films in EGFET measurement were examined with pH buffer solutions in a pH range of 2–12 at room temperature. The sensing films annealed at 550°C demonstrated a high voltage and current sensitivity at 67.6 mV/pH and 1.033 (µA)½/pH, with linearity values of 0.9968 and 0.9991, respectively. Moreover, the annealed 550°C ZnCo2O4 film exhibited low hysteresis at 4.99 mV and high retention stability. The results revealed that the pH sensing of the ZnCo2O4 EGFET device showed a super-Nernstian sensitivity, which indicated the influence of the surface properties of the annealed film. Therefore, the ZnCo2O4 film should be considered a potential option for the pH sensing layer in EGFET applications. [ABSTRACT FROM AUTHOR]

Electrochromic materials have good development prospect under the development concept of promoting low carbon and energy saving. In order to explore the efficient, simple and excellent preparation process, the polymer electrochromic film was prepared by the electrostatic spray method combined with the in-situ elution method. According to the color adaptability and solubility of the electrolyte salt, tetrabutylammonium perchlorate (TBAP) was selected as the template, and different proportions of electrolyte salt were added to the easy-to-process TPA-OMe-PA solution, then film was deposited on the surface of the ITO glass by electrostatic spray technology. After that, the electrolyte salt was precipitated by in-situ washing method. The morphology of the film was analyzed using scanning electron microscope, and the electrochromic properties of the film were studied using the electrochemical workstation combined with ultraviolet/visible/infrared spectrometer. The research results show that the polymer film prepared by electrostatic spray technology and in-situ elution method have multi-level pore structure and excellent electrochromic properties. Especially when the electrolyte content is 33.3%(mass fraction), the multi-layer porosity is the highest, and the electrochromic performance is the best. The bleaching time/coloration time is reduced to 0.6 s/1 s, and the coloration efficiency reaches 608.2 cm2·C-1, which is the best record for the polyamide based electrochromic film.

The development of novel materials is essential for the next generation of electric vehicles and portable devices. Tin oxide (SnO2), with its relatively high theoretical capacity, has been considered as a promising anode material for applications in energy storage devices. However, the SnO2 anode material suffers from poor conductivity and huge volume expansion during charge/discharge cycles. In this study, we evaluated an approach to control the conductivity and volume change of SnO2 through a controllable and effective method by confining different percentages of SnO2 nanoparticles into carbon nanotubes (CNTs). The binder-free confined SnO2 in CNT composite was deposited via an electrostatic spray deposition technique. The morphology of the synthesized and deposited composite was evaluated by scanning electron microscopy and high-resolution transmission electron spectroscopy. The binder-free 20% confined SnO2 in CNT anode delivered a high reversible capacity of 770.6 mAh g−1. The specific capacity of the anode increased to 1069.7 mAh g−1 after 200 cycles, owing to the electrochemical milling effect. The delivered specific capacity after 200 cycles shows that developed novel anode material is suitable for lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Zinc-ion energy storage devices are inexpensive and safe, benefitting from the abundance of Zn metal and high chemical stability. However, their electrochemical performance is poor, owing to the unstable Zn stripping/plating process of the Zn metal anode and the occurrence of side reactions. In this study, 3D porous reduced graphene oxide-coated Zn (rGO@Zn) was prepared via electrostatic spray deposition (ESD) and used as an anode for aqueous hybrid Zn-ion capacitors (ZICs). ESD is a cost-effective one-step technique that affords excellent control over the deposition morphology. Coating 3D porous rGO with a large surface area on Zn foil, resulted in a low charge transfer resistance and small voltage hysteresis (44.5 mV) with a long cycle life of over 3000 h. Moreover, the energy density improved at high rates (25 Wh kg−1 at 10,882 W kg−1) in aqueous hybrid ZICs. In-situ synchrotron transmission X-ray microscopy and optical microscopy analyses revealed that the formation of dendrites was inhibited in the as-fabricated ZICs. Furthermore, the conductive rGO on the surface of the Zn anode stabilized the electric field during the Zn stripping/plating process, and the functional groups guided the Zn2+ deposition sites, resulting in uniform Zn deposition during cycling and improved electrochemical performance. [Display omitted] [ABSTRACT FROM AUTHOR]

We have fabricated blend films comprising 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) as a semiconducting small molecule and poly(methyl methacrylate) (PMMA) as an insulating polymer by electrostatic spray deposition (ESD). A thin film (5 nm) of molybdenum trioxide (MoO3) was evaporated on the entirety of the active layer surface. Then, we found that the off-state current in OFETs using the TIPS pentacene/PMMA blend films apparently increased. This result probably indicates the formation of a conductive surface channel due to the MoO3 deposition. In this study, we performed morphological and chemical analyzes. In consequence, we found that only Mo atoms (not together with O atoms) penetrated into TIPS pentacene and oxidation of Mo to MoO x could enhance charge transfer between neighboring TIPS pentacene molecules. Furthermore, this study demonstrated that the off-state current could be modulated by changing the ambient condition, such as relative humidity. [ABSTRACT FROM AUTHOR]

The chemical instability of perovskite oxides containing Sr is a critical issue for the long-term operation of solid oxide fuel cells. In this study, we demonstrate a remarkable improvement in the chemical and electrochemical stability of a heterostructured La0.6Sr0.4CoO3-δ (LSC)-Ce0.9Gd0.1O1.95 (GDC) electrode. Electrostatic spray deposition was employed to fabricate heterostructured nanoparticles in a single step with a coaxial nozzle supplying the LSC powders in the core nozzle and the GDC precursors in the shell nozzle. Moreover, the reducing fuel added to the GDC precursor solution induced the sol-gel combustion reaction in the droplet to form a uniform nanocrystalline GDC coating with high surface coverage. The high surface coverage of GDC on the LSC more significantly improved long-term stability compared with than of the bare LSC cathode at a constant current density of 1 A/cm2 at 600°C for 100 h.

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• Si-based bioactive glass coatings fabricated by coupling sol-gel and electrospray. • Compositional optimization of S85, S75, and S58 coatings on Ti6Al4V substrate. • Microstructural tunning of homogeneous BG coatings as a function of ESD parameters. • From very porous coral-type coating morphology to a more compacted cauliflower one. • In-vitro investigation after 24 h immersion in simulated body fluid. For the first time, the sol-gel method was coupled with electrostatic spray deposition (ESD) to fabricate nanotextured bioactive glass (BG) coatings with a controlled microstructure in a one-pot-process. Three BG compositions belonging to the SiO 2 -CaO-P 2 O 5 system (S85, S75, and S58) were homogeneously deposited on metallic Ti6Al4V substrates starting from the atomization of precursor solutions. All coatings displayed an amorphous character, as confirmed by XRD. A wide variety of innovative BG morphologies were obtained, tuning the key parameters of ESD, leading from highly porous coral-like to compact reticular-type coatings. The bioactivity, in terms of apatite formation, of as-deposited coatings was tested by immersion in simulated body fluid solution. Textural properties were found to play an important impact in its biological performance. Highly porous ESD-coatings exhibited remarkable bioactivity for S75 and S58 compositions, compared with more compacted ones of equal formulations. S85 composition was found extremely reactive regardless of the coating microstructure. [ABSTRACT FROM AUTHOR]

Graphene-based materials such as graphene oxide (GO) and chemically reduced graphene oxide (rGO) thin films have been fabricated using electrostatic spray deposition (ESD), followed by thermal annealing under Ar/H2 atmosphere. The thickness and surface morphology of thin films of GO and rGO on silicon substrates were controlled by varying deposition time and content of GO/rGO in tetrahydrofuran (THF) solution. Here, we present a comparative analysis between GO and rGO thin films. Water contact angle (WCA) measurements of these thin films were ~88° for the GO films and >127° for the rGO films. We discuss how their hydrophobic behaviour is influenced by removal of oxygen-containing functional groups during the reduction process. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) porous NiCo 2 N@C composite was deposited on nickel foam substrate through the electrostatic spray deposition (ESD) technique followed by a post-annealing process under ammonia atmosphere. The prepared reticular-structured NiCo 2 N@C film used as binder-free anode for lithium-ion batteries (LIBs) can exhibit excellent electrochemical performance. It delivers high initial discharge capacity of 1215.8 mAh g−1 at a current density of 1 A g−1 and can reach 1630.9 mAh g−1 after 400 cycles. The electrode also shows a superior rate capability with 955.4 mAh g−1 at 10 A g−1 current density. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The current study was initiated in order to evaluate the adhesion strength of thin and porous hydroxyapatite (Hap) coatings on titanium (Ti) substrates deposited by the low temperature electrospraying method. The nanocrystalline hydroxyapatite powder was synthesized by coprecipitation method using eggshell biowaste as a nontoxic and natural source of the calcium precursor. Five hydroxyapatite coatings were electrosprayed onto Ti substrates by varying the concentration (0.05 and 0.1 wt%) of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) polymers in Hap suspensions. It has been shown that the adhesion strength of composite polymer–Hap coatings increased with increasing polymer concentration and the highest value (8.75 ± 0.75 MPa) was measured for the sample containing 0.1 wt% of PVP. The reason for the change in bonding strength was ascribed owing to microstructural changes caused by polymer addition whereas on one hand lower adhesion strength in Hap–0.1PEG was caused by the presence of separated polymer contained islands, and hence, weaker adhesion to substrate was found in this sample. On the other hand, more uniform, homogeneous, and denser microstructure resulted in an increasing cohesive strength inside the Hap–0.1PVP layer which lead to stronger mechanical bonding at the coating–substrate interface.

Commercialization of thin film manufacturing is limited due to the long process time and fabrication cost. To solve these problems, the intense pulsed light sintering method was proposed in this paper. This novel sintering process using xenon lamp irradiation accomplished sintering in milliseconds in ambient air. For evaluation of the sintering effects, wide ranges of irradiation energy densities and substrate temperatures were investigated. The additional thermal energy from bottom-heating results in reducing the required photonic energy density. A flash light sintering process was applied to fabricate a lanthanum strontium manganese (La 0.8 Sr 0.2 Mn 1 O 3-δ) perovskite structure used in energy and memory devices. The La 0.8 Sr 0.2 Mn 1 O 3-δ thin film was coated by an electrostatic spray deposition (ESD) technique, using chemical deposition. This ESD technique is suitable for the flash light sintering process because a wet chemical method facilitates rapid and low-cost commercial fabrication. After the LSMO thin films were coated, the conventional thermal and flash light sintering processes were conducted, and the properties of the LSMO thin film were evaluated for remnant organics, electrical conductivity, crystallinity, and surface morphology. Flash light sintering delivers a complete sintering process in under 1 s, eliminating the frequent obstacles inherent in thermal sintering. [ABSTRACT FROM AUTHOR]

An in-situ temperature-controlled Raman spectroscopy aided unique electrode fabrication technique has been developed for Li-ion battery applications, ensuring superior electrochemical quality of the multi-porous LiCoO 2 films with higher stoichiometric purity of high temperature (HT)-LiCoO 2 phase, by observing the structural changes during the fabrication process and thus confirming the transformation from the low temperature (LT)-LiCoO 2 phase. This much desired simple process is not only free of any sort of binders or carbon additives but also works at atmospheric pressure, leading to a very simple deposition technique using a homemade and inexpensive set-up. Also, the time of depositions were varied and resultant films we investigated for their electrochemical performance. The high-resolution scanning electron microscope (SEM) observation has revealed not only a μm-size porous structure but also three-dimensional cross-link with 10 nm-level pores of the material, which ensured the much-desired porosity for high-performance cathodes. • Preparation process of high quality HT-LiCoO 2 electrode by a simple and a unique deposition technique. • Fabrication of thin films with additives and binders free. • Purity and phase formation monitored by in-situ analysis temperature-controlled Raman analysis. • Formation of a controlled double porous layers with high quality electrode. • The effect of the deposition parameters on the morphology and the electrochemical properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • NiO-MWCNT films are deposited by electrostatic spray deposition. • The ionic and electronic conductivity of NiO films is enhanced by the MWCNT. • The coloration efficiency is enhanced with MWCNT well dispersed in the NiO. • The cycling durability of NiO improves at least 3 times with 0.5% of MWCNT. Abstract In this work, the effect of multi-walled carbon nanotubes on the electrochromic properties of compact NiO thin films prepared by electrostatic spray deposition was investigated. Noticeably, a 0.5 vol% of MWCNTs between 10–30 nm in diameter enhances the electrochromic performance of NiO, such as coloration efficiency (25.8 to 31.1 cm2/C), coloration kinetics (0.04 to 0.14 s−1) and cycling durability (1600–3900 cycles). The coloration efficiency and reversibility of the electrochemical reaction are related to the dispersion of MWCNTs throughout the film, while the reaction kinetics and cycling durability are attributed to an improvement in electronic and ionic conductivity. [ABSTRACT FROM AUTHOR]

A new type of Zn 2 VO 4 /ZnO/carbon composite (three-dimensional porous architecture) was firstly fabricated on a Ni-metal foam substrate thorough a facile electrostatic spray deposition (ESD) method followed by a calcination process. As a binder-free electrode in high performance lithium-ion batteries (LIBs), the composite electrode displays an outstanding long cycling performance, and it exhibits a high specific capacity of 930.8 mAh g−1 at 2 A g−1 even after 800 cycles without any capacity fading. And, the composite also shows a good rate performance with specific charge capacities of 742.1, 658.7, 804.9, 567.3 and 519.3 mAh g−1 at 0.1, 2, 5, 10 and 12 A g−1, respectively. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract An optimization of the oxygen electrode microstructure needs to be addressed to improve the performance of solid oxide fuel cell (SOFC) since the kinetics of the oxygen reduction reactions (ORR) in the cathode remains the main limiting factor. In this work, the electrochemical properties of the Pr 6 O 11 architectured electrode are investigated as a function of the microstructure of the active functional layer (AFL) prepared by electrostatic spray deposition (ESD) on Ce 0.9 Gd 0.1 O 2-δ (GDC) electrolyte. An optimization of the AFL microstructure is investigated varying sintering temperature from 600 °C to 1000 °C for 2 h in air. The effect of sintering temperature on the AFL microstructures is visualized and discussed thanks to FIB/SEM (focus ion beam/scanning electron microscopy) reconstructions. The composition and thickness of a CCL current collecting layer (CCL), deposited by screen-printing (SP) on the top of this AFL, are optimized as well. The nature of the CCL is either Pr 6 O 11 , La 0.7 Sr 0.3 MnO 3− δ (LSM) or La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ (LSCF) and the thickness is varied from 15 to 60 μm. Moreover, the compatibility of the Pr 6 O 11 electrode with GDC is checked over 10 days in air at 800 °C. Graphical abstract Image 1 Highlights • The microstructure of the Pr 6 O 11 functional layer strongly affects the performance. • Pr 6 O 11 layer is the main active participating layer in oxygen reduction reaction. • The current collector must be a good electronic conductor and 20–30 μm thick. • R pol of 0.02 Ω cm2 at 600 °C is found for pure Pr 6 O 11 AFL electrode topped by LSM. • Pr 6 O 11 electrode shows good compatibility with GDC over 10 days in air at 800 °C. [ABSTRACT FROM AUTHOR]

In this work, a novel flexible electrically resistive-type MXene/Thermoplastic polyurethanes(TPU) based strain sensors was developed by a composite process of electrospinning (ES) and electrostatic spray deposition (ESD). Compared with other deposition processes, the sensing layer prepared by ESD has better adhesion to the ES TPU nanofiber membrane and is not easy to crack during the stretching process, thereby greatly improving the working range of the strain sensor. Furthermore, we obtained the sandwich structure easily by ES on the surface of the sensing layer again. This will help make the stress distribution more uniform during the stretching process and further increase the strain sensing range. The ESD-ES strain sensors were attached on skin to monitor various human motions. The results demonstrate that our ESD-ES strain sensors have wide application prospects in smart wearable device.

Abstract The effect of inert coating materials such as Nafion on the non-lithiated LiV 3 O 8 cathode of lithium-metal rechargeable batteries was studied. This uniform and thin coating layer was deposited using electrostatic spray deposition to suppress the crack formation caused by volume expansion and prevent the dissolution of vanadium in the electrolyte. The Nafion coated LiV 3 O 8 electrode exhibited a higher discharge capacity and better capacity retention after 200 cycles (150.86 mAh g−1 and 62.9%, respectively) than the bare LiV 3 O 8 electrode (113.31 mAh g−1 and 46.8%, respectively). The Nafion coated LiV 3 O 8 electrode was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and inductively coupled plasma mass spectrometry. Its electrochemical performance was analyzed using a battery testing system and impedance spectroscopy. Our findings show that the inert coating layer on the LiV 3 O 8 cathode plays an important role in improving its electrochemical performance. Highlights • An inert material, Nafion, was coated on the surface of LiV 3 O 8 electrode. • Electrostatic spray deposition ensured a uniform and homogeneous coating layer. • The coating layer prevented vanadium dissolution and suppressed volume expansion. • The Nafion coating layer led to a higher discharge capacity and better retention. [ABSTRACT FROM AUTHOR]

Abstract Electrostatic spray deposition (ESD) is a technique with characteristics of uniform atomization and ultrafine powder distribution due to the stable formation of controllable small droplets. Based on this advantage, we demonstrated uniformly distributed ultrafine diamond particles for fabricating thin grinding layer by ESD technique. The atomization spray process of the charged droplets enclosed ultrafine diamond particles in the electrostatic field was revealed. The average number and standard deviation of particles were analyzed to meet satisfactory atomization effect in single droplet. The number, distribution uniformity, and distribution density, distribution range of particles were evaluated quantitatively by regulating electrode voltage, liquid flow, and receiving height. The corresponding optimum values of 781, 88%, 10.4 × 10−3 μm−2 and 5 mm were obtained. Thin diamond abrasive layers at different injection times were formed to preliminarily fabricate ultrafine grinding tool. Results indicate that the distribution of particles on the cross-section of the thin layer was better, with a distribution uniformity of 84.52%. Graphical abstract Unlabelled Image Highlights • Electrostatic spray deposition (ESD) achieves excellent distribution of diamond particles. • Particles characteristics in a single droplet affect the global distribution. • Characteristics and mechanisms of uniformly distributed particles are controlled by regulating various parameters. • A thin diamond abrasive layer is fabricated to prepare ultrafine grinding wheel. • ESD has significant implications for stable formation of small droplets and particles. [ABSTRACT FROM AUTHOR]

Abstract In this study, organic field-effect transistors (OFETs) based on blend films comprising 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and polystyrene (PS) were fabricated. The blend films were prepared by electrostatic spray deposition (ESD). A vertically phase-separated structure (TIPS pentacene (top)/PS (bottom)) can be spontaneously formed without additional treatments such as solvent-vapor annealing, which is significantly different from the blend with poly(methyl methacrylate) (PMMA). Due to the sharp phase-separated interface, OFETs based on the TIPS pentacene/PS blend films exhibited superior characteristics and operational stability. Graphical abstract Image 1 Highlights • Blend films comprising TIPS pentacene and PS were prepared by ESD. • Vertical phase-separation was spontaneously induced without additional treatments. • OFETs based on TIPS pentacene/PS blend films were fabricated. • OFETs with the sharp phase-separated interface exhibited superior characteristics. [ABSTRACT FROM AUTHOR]

Abstract Electrosprayed BiVO 4 adopts a nanopillar structure formed by diffusion-limited aggregation, which maximizes the surface area of the nanopillars. However, increasing the interfacial area between an electrode and the electrolyte through nanostructuring enhances the overall interfacial activity for solar water splitting. For this purpose, the pH of the precursor solution used for electrospraying BiVO 4 was altered by adding ammonium hydroxide, thereby inducing a drastic change in the morphology of BiVO 4. The previously demonstrated nanopillar morphology of electrosprayed BiVO 4 was transformed into a nanofern structure that increased the photocurrent density of BiVO 4 from 0.82 to 1.23 mA·cm−2 at 1.2 V vs. Ag/AgCl. The produced films were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and electrochemical impedance spectroscopy. Highlights • BiVO 4 nanopillar morphology were tuned to nanoferns with a facile one-pot method. • Nanoferns showed the fast photoresponse due to enhanced photoelectrochemical sites. • The photocurrent density of BiVO 4 nanoferns reached to 1.23 mA·cm−2 at 1.2 V vs Ag/AgCl. • The structural and morphological properties of BiVO 4 nanoferns were characterized. [ABSTRACT FROM AUTHOR]

A high areal sulfur loading in a carbon-based cathode together with a high cell capacity is key to the design of lithium-sulfur batteries guaranteeing a superior energy density for use. However, a high sulfur loading produced using traditional blade coating techniques results in many technical issues such as sluggish electron/ion transport kinetics and cracking of the electrodes. Here a well designed two-step electrostatic spray deposition (ESD) technique is proposed to prepare a flexible, multilayer carbon electrode with a high sulfur areal loading, in which different carbon components by a careful selection are used for different functions in each layer. The unique "aerosol deposition" in the ESD creates buffer voids in the electrode, ensuring fast infiltration of the electrolyte and releasing the internal stress of the electrode thus avoiding the cracking of thick electrodes. With such an integrated design, the as-prepared cathode exhibits excellent flexibility, a long cyclic stability with a low capacity decay of 0.064% per cycle at 1 C for 500 cycles and a high rate capability of 736 mAh g −1  at 2 C. Moreover, a high areal sulfur loading of 9.4 mg cm −2 with an areal capacity of 6.2 mAh cm −2 at 0.1 C has been achieved. [ABSTRACT FROM AUTHOR]

We demonstrate fabrication of films of highly textured bismuth oxide (Bi 2 O 3 ) pillars via electrostatic spray deposition and test the performance of these films as photoanodes in photoelectrochemical water splitting. The β-Bi 2 O 3 and α-Bi 2 O 3 phases were identified and distinguished using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The β-Bi 2 O 3 pillars of optimized thickness exhibited a photocurrent density of 0.97 mA⋅cm −2  at 0.5 V vs Ag/AgCl. The tetragonal β-Bi 2 O 3 pillars had enhanced visible light absorbance compared to α-Bi 2 O 3 as well as other metal oxides like ZnO and TiO 2 . Tauc plot analysis of film absorbance showed a decrease in the bandgap of the β-Bi 2 O 3 phase to 2.5 eV. In Na 2 SO 3 electrolyte, a hole scavenger, the onset voltage for the β-Bi 2 O 3 phase was shifted to a more negative value (−0.4 V), which increased photocurrent density. The electron concentration reached its highest value of 9.1 × 10 20  cm −3 for the film with the highest photocurrent density. [ABSTRACT FROM AUTHOR]

One major challenge associated with proton exchange membrane fuel cells is to preserve higher proton conductivity under low-humidity atmosphere. Elevation of water uptake in the perfluorinated polymeric membrane is crucial for the facilitated transportation of proton, which dominates the fuel cell performance. Development of an intrinsic mechanism that controls water balance through the membrane electrode assembly (MEA), eliminates the need for external water management system and thus makes the system suitable for portable applications, where size is an important criterion to be considered. Herein, we report a nano-sized dense-structure (NSDS) layer coated onto the conventional catalyst layer, forming a dual-layered electrode architecture that is favorable in promoting the self-humidification process. This self-humidifying layer is fabricated by the electrostatic spray deposition with sufficiently low deposition rate, which allows for a creation of more uniformly distributed porous structure with diameters smaller than 80 nm, enabling recirculation of the water generated for proper humidification. When experimentally investigated, the MEA employing the dual-layered electrode reveals a 3.15 times elevated current density at 0.6 V than conventional MEA under 0% relative humidity. Mechanism for the water retention in the proposed electrode is further evaluated by X-ray computed tomography, which reveals dramatically increased tortuosity of 4.43 for the NSDS layer in comparison to 1.9 for the conventional catalyst layer. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cathode particle size was controlled using electrostatic spray deposition. • A pull-off test was performed to directly assess the interface properties. • Strong correlation was revealed between interface contact coverage and performance. • A significantly high peak power density of 1.87 W cm−2 is achieved at 600 °C. The interface between the cathode and the electrolyte is critical in the electrochemical performance of intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, the correlation between the structural properties at the interface and the electrochemical performance is investigated with a focus on the ohmic resistance. Electrostatic spray deposition (ESD) is used to optimize the cathode particle size and distribution by controlling the solvent evaporation rate. A mechanical pull-off test is performed to directly assess the structural properties at the interface. Furthermore, electrochemical impedance spectroscopy (EIS) is employed with an equivalent circuit model to establish a quantitative correlation between the contact coverage at the interface and the interfacial resistance. By maximizing contact coverage, a significantly high peak power density of 1.87 W cm−2 is achieved at 600 °C in a Ni-Gd 0.1 Ce 0.9 O 1.95 (GDC)-based single cell. The findings indicate that the proposed approach effectively achieves the desired structural properties, thereby enhancing the performance of IT-SOFCs with significant implications for the design and optimization. [ABSTRACT FROM AUTHOR]

Significant efforts have recently been undertaken to develop highly efficient solid oxide cells for high-temperature steam electrolysis (SOEC). Implementing new materials and microstructures that would improve the performance and durability of this technology remains a major issue. For this purpose, a nano-structured PrO 1.833 material coated by the electrostatic spray deposition (ESD) technique was studied as a promising active oxygen electrode for SOEC application. The study was performed considering the PrO x as the functional layer and strontium-doped lanthanum manganite (LSM) as the current collecting layer on a standard half-cell supported by a typical Ni-YSZ cermet, a YSZ electrolyte, and a gadolinium-doped ceria (GDC) barrier layer. The electrochemical characterizations showed promising initial performance at 700 °C in SOEC mode (− 1 A cm−2 at 1.4 V with H 2 O/H 2 = 90 vol%/10 vol%). In addition, a reasonable degradation rate of ∼5.8% kh−1 was obtained at 700 °C within 1000 h of SOEC operation. The structural and elemental evolutions were analyzed with micrometer size resolution all along the functional layer thickness using synchrotron μ-X-ray diffraction and fluorescence. The electrode degradation was primarily attributed to the phase transitions of PrO 1.833. In particular, the structural analyses of the sample aged under applied current revealed a small quantity of PrO 1.5≤x≤1.7 phase at the GDC/AFL (active functional layer) interface which is expected to be less conductive than PrO 1.833 , along with PrO 1.714 and GDC phases. Finally, additional structural characterizations were performed on samples annealed at different temperatures and dwell times: 700 °C for 1000 h and 800 °C for 700 h, respectively. The results are discussed to provide a better understanding of the stability of the praseodymium oxide. • SOEC long-term test of a nanostructured PrO x electrode. • No significant interdiffusion of the chemical elements detected by SEM-EDX. • Phase decomposition characterized by synchrotron μ-XRD and μ-XRF. • Only ∼5.8% kh−1 degradation rate obtained at 700 °C for 1000 h of SOEC operation. • A better understanding of the aging of nanostructured PrO x for electrolysis. [ABSTRACT FROM AUTHOR]

Here, we studied the particle release rate during Electrostatic spray deposition of anatase-(TiO 2 )-based photoactive coating onto tiles and wallpaper using a commercially available electrostatic spray device. Spraying was performed in a 20.3 m 3 test chamber while measuring concentrations of 5.6 nm to 31 μm-size particles and volatile organic compounds (VOC), as well as particle deposition onto room surfaces and on the spray gun user hand. The particle emission and deposition rates were quantified using aerosol mass balance modelling. The geometric mean particle number emission rate was 1.9 × 10 10 s −1 and the mean mass emission rate was 381 μg s −1 . The respirable mass emission-rate was 65% lower than observed for the entire measured size-range. The mass emission rates were linearly scalable (±ca. 20%) to the process duration. The particle deposition rates were up to 15 h −1 for <1 μm-size and the deposited particles consisted of mainly TiO 2 , TiO 2 mixed with Cl and/or Ag, TiO 2 particles coated with carbon, and Ag particles with size ranging from 60 nm to ca. 5 μm. As expected, no significant VOC emissions were observed as a result of spraying. Finally, we provide recommendations for exposure model parameterization. [ABSTRACT FROM AUTHOR]

The deposition and characterization of magnetic metal-oxide, Eu 1− x Sr x CoO 3 ( x = 0.2, 0.5) thin films using an electrostatic spray method are presented. The nano-sized particles were electro-sprayed from a colloidal suspension onto Pt/TiO 2 /SiO 2 /Si substrates at room temperature under ambient pressure. X-ray diffraction patterns showed a perovskite tetragonal structure with an I 4/ mmm space group. Optical and scanning electron microscopy of the thin films revealed their crack-free and uniform nature. The temperature-dependent magnetization showed a ferromagnetic-paramagnetic transition above 350 K. Magnetic moments hysteresis loops demonstrate that the thin films exhibited a hard ferromagnetic state at 10 K and a soft ferromagnetic one at room temperature. The Hall measurement revealed metallic behavior at room temperature, confirming the transition from a metallic state to an insulating one at T > 300 K. The correlation is explained based on the double exchange interaction and spin state transitions at both low and high temperatures. [ABSTRACT FROM AUTHOR]

Bottom-gate top-contact organic field-effect transistors (OFETs) based on 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and poly(methyl methacrylate) (PMMA) blends were fabricated using electrostatic spray deposition (ESD). Solvent-vapor annealing (SVA) was conducted as a post-deposition treatment to induce vertical phase separation of the blend films. The phase-separated morphology was investigated by selective etching of TIPS pentacene with cyclohexane. A relatively rough surface with some pinholes was observed in the etched film without SVA, suggesting that vertical phase separation was not sufficient during the ESD process. The phase-separated morphology was modified remarkably by SVA, and a SVA-treated blend device with a well-defined phase-separated structure exhibited enhanced performance and operational stability compared to a device based on the as-deposited blend. [ABSTRACT FROM AUTHOR]

Mechanical resistance of Al 2 O 3 + TiO 2 nanocomposite ceramic coating deposited by electrostatic spray deposition method onto X10CrAlSi18 steel to thermal and slurry tests was investigated. The coating was produced from colloidal suspension of TiO 2 nanoparticles dispersed in 3 wt% solution of Al 2 (NO 3 ) 3 , as Al 2 O 3 precursor, in ethanol. TiO 2 nanoparticles of two sizes, 15 nm and 32 nm, were used in the experiments. After deposition, coatings were annealed at various temperatures, 300, 1000 and 1200 °C, and next exposed to cyclic thermal and slurry tests. Regardless of annealing temperature and the size of TiO 2 nanoparticles, the outer layer of all coatings was porous. The first five thermal cycles caused a rapid increase of aluminum content of the surface layer to 30–37 wt%, but further increase in the number of thermal cycles did not affect the aluminum content. The oxidation rate of coating-substrate system was lower during the thermal tests than during annealing. The oxidation rate was also lower for smaller TiO 2 particles (15 nm) forming the coating than for the larger ones (32 nm). The protective properties of Al 2 O 3 + TiO 2 coating against intense oxidation of substrate were lost at 1200 °C. Slurry tests showed that coatings annealed at 1000 °C had the best slurry resistance, but thermal tests had weakened this slurry resistance, mainly due to decreasing adhesion of the coating. [ABSTRACT FROM AUTHOR]

In this study, porous manganese oxide (MnOx) thin films were synthesized via electrostatic spray deposition (ESD) and evaluated as pseudocapacitive electrode materials in neutral aqueous media. Very interestingly, the gravimetric specific capacitance of the ESD-based electrodes underwent a marked enhancement upon electrochemical cycling, from 72 F.g-1 to 225 F.g-1, with a concomitant improvement in kinetics and conductivity. The change in capacitance and resistivity is attributed to a partial electrochemical phase transformation from the spinel-type hausmannite Mn3O4 to the conducting layered birnessite MnO2. Furthermore, the films were able to retain 88.4% of the maximal capacitance after 1000 cycles. Upon verifying the viability of the manganese oxide films for pseudocapacitive applications, the thin films were integrated onto carbon micro-pillars created via carbon microelectromechanical systems (C-MEMS) for examining their application as potential microelectrode candidates. In a symmetric two-electrode cell setup, the MnOx/C-MEMS microelectrodes were able to deliver specific capacitances as high as 0.055 F.cm-2 and stack capacitances as high as 7.4 F.cm-2, with maximal stack energy and power densities of 0.51F.cm-2 and 28.3 mW.cm-3, respectively. The excellent areal capacitance of the MnOx-MEs is attributed to the pseudocapacitive MnOx as well as the three-dimensional architectural framework provided by the carbon micro-pillars. [ABSTRACT FROM AUTHOR]

Carbon-doped ZrO 2 film with three-dimensional (3D) grass-like architecture was fabricated directly on interdigitated electrodes via one-step electrostatic spray deposition (ESD) using zirconatrane precursor without any additional carbon source and template. A one-step synthetic route was presented in which no additional film fabrication steps were required. The mesoporous micrograss structure comprised numerous interconnected nanoleaves. The synergistic combination of the unique morphology and carbon doping can offer superior room-temperature gas sensing activity for detecting alcohol and acetone. The sensitivity of the devices to methanol, ethanol, n -propanol and acetone was also tested. The gas sensing test results showed that the 3D hierarchical carbon-doped ZrO 2 based sensor exhibited excellent gas sensing performance at room temperature in terms of high response, short response/recovery times, good repeatability, long-term stability and superior selectivity to acetone, and has much higher response in comparison with the ZrO 2 sensor derived from commercial starting material. [ABSTRACT FROM AUTHOR]

Fabrication of a patterned hydrogen-bonded organic framework (HOF) films on a large scale is an extreme challenge. In this work, a large area HOF film (30 × 30 cm 2 ) is prepared via an efficient and low-cost electrostatic spray deposition (ESD) approach on the un-modified conductive substrates directly. Combining the ESD with a template method, variously patterned HOF films can be easily produced, including deer- and horse-shaped films. The obtained films exhibit excellent electrochromic performance with multicolor change from yellow to green and violet, and two-band regulation at 550 and 830 nm. Benefiting from the inherently present channels of HOF materials and the additional film porosity created by ESD, the PFC-1 film could quickly change color (within 10 s). Furthermore, the large-area patterned EC device is constructed based on the above film to prove practical potential application. The presented ESD method can be extended to other HOF materials; thus, this work paves a feasible path for constructing large-area patterned HOF films for practical optoelectronic applications., (© 2023 Wiley-VCH GmbH.)

Semiconductor metal oxide films of copper-doped tin oxide (Cu-SnO2), tungsten oxide (WO3) and indium oxide (In2O3) were deposited on a platinum coated alumina substrate employing the electrostatic spray deposition technique (ESD). The morphology studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows porous homogeneous films comprising uniformly distributed aggregates of nano particles. The X-ray diffraction technique (XRD) proves the formation of crystalline phases with no impurities. Besides, the Raman cartographies provided information about the structural homogeneity. Some of the films are highly sensitive to low concentrations of H2S (10 ppm) at low operating temperatures (100 and 200 °C) and the best response in terms of Rair/Rgas is given by Cu-SnO2 films (2500) followed by WO3 (1200) and In2O3 (75). Moreover, all the films exhibit no cross-sensitivity to other reducing (SO2) or oxidizing (NO2) gases.

Two-dimensional porous metallo-supramolecular polymers (MSPs) have shown promising prospects for electrochemical-controlled functional devices as their highly reversible metal-centered redox chemistry. However, parallel efforts to solution-processable large-area uniform film based on high-quality MSPs have encountered with limited success. Herein, we develop a scalable method for synthesizing MSP-Fe with "gram" scale by coordinating 1,3,5-tris(4-(2,2′:6′,2″-terpyridyl)phenyl)benzene with Fe(II) ions. The uniform MSP-Fe film is assembled on a transparent conductive substrate by electrostatic spray technology. The obtained MSP-Fe films exhibit excellent electrochromic performance and energy storage property simultaneously, such as ultrahigh coloration efficiency of 1103.9 (± 100) cm2 C−1, fast switching speed (< 1.5 s), large optical contrast (> 71.7%), and high specific capacity (12.01 mAh g−1). More importantly, the degradation of optical contrast is only 3% after 10,000 cycles, proving the remarkable cycle stability of the MSP-Fe film. We further demonstrate a smart energy-storage indicator assembled by the MSP-Fe films, in which the energy-storage level is visually perceptible and recognizable in real-time. Furthermore, a large-area semi-solid-state electrochromic device (225 cm2) is successfully constructed based on MSP-Fe films, which achieves a uniform, fast, and reversible color variation across the device. [Display omitted] • Two-dimensional metallo-supramolecular polymer of MSP-Fe was successfully synthesized at the "gram" scale. • Large-scale MSP-Fe films were obtained on rigid and flexible substrates using electrostatic spray deposition technology. • The excellent electrochromic energy storage property was achieved by the MSP-Fe film. • The developed electrochromic energy storage indicator could display the energy storage status via the color variation. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) porous ZnMn 2 O 4 thin films on nickel foam substrates have been successfully synthesized through electrostatic spray deposition (ESD) method followed by an annealing process for lithium-ion battery anodes. These films exhibit excellent cycling performance with a reversible capacity of around 982 mAh g −1 after 100 cycles at 400 mA g −1 . The ZnMn 2 O 4 films also display good rate capability with 455 mAh g −1 at 5 A g −1 . The superior battery performances of ZnMn 2 O 4 films are ascribed to 3D porous ZnMn 2 O 4 film directly deposited on Ni foam, which can offer effective empty space to accommodate the large volume variation during cycling, increase reaction sites, and improve the electron transport. The ESD strategy is facile, cost-effective, which can be potentially utilized to construct other 3D porous mixed transition-metal oxides materials as well. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) porous ZnCo 2 O 4 thin films on nickel foam substrates have been fabricated through a facile strategy of electrostatic spray deposition (ESD) followed by annealing in Ar atmosphere for lithium-ion battery anodes. The obtained ZnCo 2 O 4 films on Ni foams show excellent cycling performance with a reversible capacity of over 1726 mAh g − 1 after 100 cycles at 400 mA g − 1 . The ZnCo 2 O 4 electrodes also present good rate capability with 811 mAh g − 1 at 5 A g − 1 . The improved electrochemical performances should be ascribed to 3D porous ZnCo 2 O 4 architecture directly grown on Ni foam current collector, due to the synergistic advantages of offering more reaction sites, effective void space to the volume variation during cycling, and improving of electron transport. It is proposed that this facile strategy of ESD technique can be extended to synthesize other 3D porous mixed transition-metal oxide materials. [ABSTRACT FROM AUTHOR]

Graded and homogeneous CGO–LSCF composite electrodes deposited by Electrostatic Spray Deposition on an YSZ substrate have been studied with and without screen-printed LSCF current collector. Impedance spectroscopy measurements have been performed in air at open circuit potential between 450 °C and 700 °C; and during isothermal treatments at 600 °C for 200 h; and at 800 °C for 12 h to estimate the relevance of such oxygen electrodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). A thin and dense CGO layer is firstly deposited to avoid any chemical reaction between LSCF and YSZ. No significant increase of the polarization resistance has been evidenced during isothermal test at 600 °C for 200 h, proving good stability of the electrode. Using a LSCF current collector layer (CCL), the polarization resistance decreases by a 1.5 order of magnitude compared to samples with single cathode functional layer (CFL). The electrochemical results do not conclusively indicate which composition presents lower polarization effects. [ABSTRACT FROM AUTHOR]

We studied the effects of solvent-vapor annealing (SVA) on the device performance of bulk-heterojunction organic photovoltaic solar cells. Electrostatic spray deposition (ESD) was used to prepare photoactive layers composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) blend. While the surface of the photoactive layer could be flattened by SVA, excessive treatment resulted in a decrease in open-circuit voltage. We attribute this to too large vertical phase separation within the P3HT:PCBM blend and accumulation of P3HT on the surface of the photoactive layer, which can induce recombination of photogenerated charges at the cathode/photoactive layer interface. A decrease in the open-circuit voltage could be prevented to some extent by depositing the photoactive layers using smaller droplets produced in the ESD process; this was probably due to the slower progress of vertical phase separation. Furthermore, introducing LiF as a hole-blocking layer between the cathode and the photoactive layer significantly reduced recombination-related leakage current, thereby preventing a decrease in open-circuit voltage. [ABSTRACT FROM AUTHOR]