Dense Films Research Articles

Electrode/electrolyte interface adjustment through adding mannitol into the solution to improve the re-discharge performance of alkaline Al-air batteries

As a high-power battery system, Al-air batteries exhibit a wide range of potential applications. However, Al-air batteries are susceptible to significant open-circuit corrosion of the aluminum electrodes when removed from the electrolyte during standby, resulting in the formation of a dense film of corrosion products on the aluminum electrode surface. This, in turn, impedes the re-discharge performance of Al-air batteries. Based on an electrode/electrolyte interface adjustment strategy, mannitol is used as the additive to be added into 4 M KOH solution to improve re-discharge performance. Experimental analyses and theoretical calculations reveal that the inclusion of mannitol enhances the re-discharge performance of Al-air batteries through a combination of hydrogen bonding and adsorption. Importantly, it is noted that mannitol has minimal impact on the battery power density. The reason for the improvement is explained reasonably by a proposed mechanism. These findings offer valuable insights for the development of Al-air batteries with high performance.

Fabrication of iron doped titanium dioxide photocatalytic nanocomposite supported by water-quenched blast furnace slag and photocatalytic degradation of wastewater

Metallurgical solid waste blast furnace water quenched slag (WBFS) was employed as carrier materials to prepare Fe–TiO2/WBFS composite photocatalyst using a sol-gel method for improving both the photocatalytic activity and the high-value utilization of metallurgical solid waste. The Fe3+ doping technology was adopted to increase the utilization of solar energy. The influencing factors and photocatalytic activity were systematically evaluated by thermogravimetry/differential thermal analyser (TG-DSC), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) method, scanning electron microscopy-energy spectrometer (SEM-EDS), X-ray photoelectric spectroscopy (XPS), UV–Vis absorption spectrum and photoluminescence spectra technology through the degradation rate of methylene blue (MB) solution. The results showed that the Fe3+ ions were successfully incorporated into the TiO2 lattice, which had no effect on the crystalline phase of TiO2 and expanded the spectral response range of TiO2 from the ultraviolet region to the visible light region. When the calcination temperature was at 450 °C and the number of Fe–TiO2 sol loading cycles was two times, the photocatalytic activity of Fe–TiO2/WBFS presented the strongest, and the degradation ratio of MB reach the maximum value of 98.9 %. A uniform and dense anatase TiO2 thin film was wrapped on the surface of WBFS. The photocatalytic activity first improved and then weakened with an increase of calcination temperature, Fe3+ doping amounts and the loading cycles of sol. The TiO2 film changed from thin to thick and uneven to uniform, until cracking and spalling phenomenon finally occurred with an increase of Fe–TiO2 sol loading cycle from 1 to 3 times. When the Fe–TiO2/WBFS was reused for four times, the degradation rate of MB could still show 67.4 %, being far higher than that of TiO2/WBFS of 25.4 %.

Influence of dissolved oxygen concentration on the electrochemical and semiconductor characteristics of passive oxide films deposited on Fe-based metallic glass coatings

Certain metals produce passive oxide film layers during use which are closely related to their corrosion resistance. The properties of the oxide film are strongly influenced by the oxygen content of the surrounding environment. This study aims to examine the impact of dissolved oxygen concentration on the corrosion and passive oxide film formed on Fe-based metallic glass coatings. In deoxygenated solutions, the coating was highly susceptible to corrosion, while exhibiting the highest corrosion potential in oxygenated solutions due to the formation of a dense oxide film. The impedance of the passive film was notably influenced by the presence of dissolved oxygen. In deoxygenated solutions, the impedance remained stable and at a minimum level. However, in oxygenated solutions, the impedance exhibited a significant increase accompanied by rapid film growth. The carrier concentration in the passive film remained low and constant in deoxygenated solutions but decreased in oxygenated ones. The composition of the passive film varied with dissolved oxygen concentration, leading to FeOOH formation in deoxygenated solutions and to the increase in Cr2O3/Cr(OH)3 ratio in oxygenated environments. Moreover, deoxygenated solutions slowed down the film growth rate, while oxygenated ones were conducive to the fast development of films, affecting their protective ability.

Nitrophenol compounds photoreduction by MnO2/ZnO thin film with impact on reducing agents

In this work, a thin layer of manganese dioxide/zinc oxide (MnO2/ZnO) was deposited on a glass substrate using a two-stage chemical bath deposition (CBD) method to optimize the photocatalytic activities in the reduction of 2-nitrophenol. The effects of ethanol and butanol as reducing agents on the surface morphology, wettability, thermal insulation, and photocatalytic activities were investigated. At 100 kX magnification, the micrographs clearly showed the MnO2 nanoparticles embedded in the thin film for the single and two-stage CBD, with the particle agglomeration being more pronounced for the two-stage CBD. ZnO has been diffused into MnO2 for both reducing agents, albeit with lower integration. In addition, the images show that the prepared catalyst in butanol gradually granulates with increasing ZnO content compared to ethanol, affecting its particle size and the active surface. The thermal insulation test reveals that the sample with 10 % ZnO reduces the temperature by 4 °C, which improves the durability and stability of the catalyst. The exact composition of the sample demonstrates the optimum photodegradation of 2-nitrophenol with an efficiency of 94.96 % (0.0301 min−1). The measurement of the water contact angle also showed an increase in the contact angle (CA) with a value of 55.6°. Based on the findings, it was found that photocatalysts using butanol as a reducing agent demonstrate higher efficiency in reducing of 2-nitrophenol as compared to ethanol due to its homogeneous distribution and large surface area. This study brought a new direction in impact of reducing agent on void free and dense thin film of the MnO2/ZnO catalyst in reducing of persistent water pollutants under visible light irradiation.

Isolation, Characterisation and Corrosion Inhibition Evaluation of 1, 3, 5-Trimethoxymethylbenzenefrom Seeds Extract of Cola nitida on Mild Steel Surface in Hyhrochloric Acid Solution

Corrosion inhibition of Mild steel in 1 M hydrochloric acid solution by 1, 3, 5-trimethoxymethylbenzene (TMMB) isolated from seeds extract of Cola nitida was studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopic methods. TMMB was isolated from seeds of C. nitida by 72 hours maceration of the chopped seeds with dichloromethane. Filtered and concentrated extract was subjected to a combination of vacuum liquid, column and thin layer chromatographic techniques. The isolated compound was characterized using Fourier Transform Infra-Red (FT-IR) spectrophotometer, proton nuclear magnetic resonance (+H-NMR), C13 – NMR and DEPT-135 NMR spectrophotmeters. The results showed that the inhibition efficiency recorded by the weight loss method increased with the increase in TMMB concentration, but decreased with increasing temperature. The inhibition efficiencies recorded by the potentiodynamic polarization and electrochemical impedance spectroscopic methods also increased with increase in the concentration of TMMB. The calculated thermodynamic parameters showed that the corrosion inhibition process was endothermic and spontaneous in nature. Potentiodynamic polarization measurements confirmed that TMMB worked as a mixed – type inhibitor considering the value of Ecorrbeing less than 85 mV. Impedance measurement revealed that the charge transfer resistance offered by TMMB to the migration of aggressive ions on the surface of mild steel in acidic solution was enough to impede corrosion. The best line of fit to the adsorption of TMMB onto mild steel surface was found in Temkin isotherm. Formation of protective dense film on the steel surface in the presence of TMMB compared to the blank was revealed by scanning electron microscopy. The molecular structure of TMMB was optimized using Gausian 09 with density functional theory [DFT/B3LYP/6-31G (d,p)]. Physical adsorption has been proposed for the adsorption of TMMB onto mild steel surface.

Acceleration of interfacial kinetics induced by regulation of Li+ desolvation process in lithium metal-based batteries

Lithium (Li) metal anode is the most promising anode for next-generation high-energy-density batteries due to the high theoretical specific capacity and the lowest redox potential. However, the uncontrollable growth of lithium dendrite and infinite volume expansion limit the development of Li metal-based batteries (LMBs). Introducing functional additives into electrolytes is considered as one of the efficient and economical strategies to suppress the Li dendrite growth and relieve the volume effect. Nevertheless, single-functional electrolyte additives can hardly comprehensively enhance the electrochemical performance of LMBs. Herein, boron-based anion receptor Tris(hexafluoroisopropyl) Borate (THFPB) is introduced into the electrolyte to weaken the interaction between the solvent and lithium ions, which regulates the lithium-ion desolvation process and enhance Li+ migration, resulting in the formation of smooth, dense, and rich-inorganic solid electrolyte interphase (SEI) film. Strikingly, with 2 wt % THFPB additive, the Li||Li cell shows an extremely long cycle life of 4200 h, and the Li||Cu cell affords a high Coulombic efficiency (CE) of 99.87 %. The THFPB-modified electrolyte shows superior universality, which enhances the cycling and rate performance of the Li||S and Li||LiFePO4 cells. Generally, this work provides a new perspective on the selection of new functional additives to achieve a long cycling life Li metal battery with great performance.

Quasi‐hexagonal nanopatterned porous cobalt ferrite thin films prepared via block copolymer self‐assembly

AbstractWe present a novel method for fabricating dense and nanopatterned porous cobalt ferrite (CoFe2O4) thin films with a remarkable thickness of 65 nm, achieved through direct block copolymer self‐assembly. By decomposing the block copolymer and inducing crystallization of the spinel phase, we successfully produce films exhibiting quasi‐hexagonal arrays of pores with an average diameter ranging from 60 to 80 nm. The resulting nanopatterned porous thin films demonstrate exceptional orderliness, as the pores are intricately designed by the cobalt ferrite grains, and the platinum substrate offers complete accessibility in the pore area. Our findings reveal high magnetization values, comparable to those of bulk CoFe2O4, in the dense film. Additionally, in the case of the nanopatterned porous film, we observed a distinctive contribution of perpendicular magnetization. This innovative approach holds great promise for advanced magnetization and thin‐film engineering applications.

Acetate-based ionic liquid engineering for efficient and stable CsPbI2Br perovskite solar cells with an unprecedented fill factor over 83%

The current investigation addresses the persistent challenge of poor ambient stability exhibited by inorganic lead halide perovskites, primarily stemming from intrinsic phase transitions and the presence of defect states. This area of research has been considerably unexplored thus far. On the other hand, the notable effects of ionic liquids (ILs) in improving both stability and efficiency of perovskite photovoltaics have been substantial. In line with these developments, this study endeavors to synergize these two critical domains by introducing an acetate (Ac)-based IL into the inorganic perovskite precursor solution to tailor the crystal growth and charge carrier dynamics in CsPbI2Br films, resulting in prolonged stability and enhanced photovoltaic performance. The integration of 1-butyl-3-methylimidazolium acetate (BMIMAc) can indeed accelerate the crystallization of the inorganic perovskite film by interacting the Ac− anion with uncoordinated Pb2+ cation in CsPbI2Br. This interaction prompts the formation of smaller grains, which in turn inhibits the creation of non-photoactive phases. Moreover, the presence of BMIMAc as a passivation agent introduces significant defect-healing capabilities, eliminated charge recombination, and increased hydrophobicity. This work endeavors to pave the way for high-efficiency, enduring, and more robust inorganic PSCs through the integration of innovative materials and advanced understanding of fundamental principles, resulting uniform and dense perovskite film. Accordingly, 1.1 mol% BMIMAc-passivated device enables an impressive efficiency of 15.6% with an unprecedented fill factor (FF) exceeding 83%. Remarkably, even after undergoing extended light-soaking for 600 h, the BMIMAc-passivated device retains approximately 85% of its initial efficiency.

MXene nanomesh for high-performance supercapacitor

The merits of excellent electrical conductivity, good hydrophilicity, and large specific capacitances render MXene film electrodes attractive in supercapacitors (SCs). However, the tortuous ion transfer in restacked nanosheets limits the electrochemical performance of dense film electrodes. To solve the ion transfer issue, we propose a strategy to produce porous films assembled by Ti3C2 nanomesh via the chemical oxidation-etching process. The rich in-plane pores in Ti3C2 nanomesh provide abundant pathways and new active sites for ion transfer/adsorption, greatly improving the electrochemical activity. Specifically, the obtained Ti3C2 nanomesh films exhibit high specific capacitances of 235 F g-1 at 1 A g-1 and 184 F g-1 at 10 A g-1 in 6 M KOH, which are ∼2 times higher than the pristine Ti3C2 films (118 F g-1 at 1 A g-1 and 90 F g-1 at 10 A g-1). Furthermore, hybrid capacitors, composed of the Ti3C2 nanomesh films as the negative electrodes and Ni-Co layered double hydroxides as the positive electrodes, in KOH electrolytes, are also demonstrated to show practicability. This work provides an opportunity to develop high-performance energy storage devices with the 2D nanomesh.

Antisolvent-Free Heterogenous Nucleation Enabled by Employing 4-Tert-Butyl Pyridine Additive and Two-Step Annealing for Efficient CsPbI2Br Perovskite Solar Cells.

All inorganic perovskite based on CsPbI2Br has attracted significant attention due to its relatively thermal stable structure compare to its hybrid counterparts. With a wide bandgap of 1.9eV and excellent light absorption capability, it has been extensively explored for applications in indoor photovoltaics and as a front absorber in tandem devices. However, the uncontrollable crystallization process during solvent evaporation and thermal annealing leads to both macroscopic defects like cracks and microscopic defects such as voids. In this study, a metastable adduct with lead (II) halides by incorporating 4-tert-butyl pyridine as a volatile Lewis base monodentate ligand in the precursor solution is formed. The strategic preferential decomposition of the adduct during the early-stage low-temperature annealing facilitated the desorption of lead (II) halides, inducing antisolvent-free heterogenous nucleation. This, in turn, promoted crystal growth during subsequent high-temperature annealing, resulting in dense films with low defect density. As a result, a maximum open-circuit voltage of 1.30V is achieved with the champion power conversion efficiency of 16.5% in CsPbI2Br-based perovskite solar cell. The work reveals a new mechanism of using Lewis acid-base adduct to obtain high quality perovskite films other than hindering crystallization in traditional way.

<i>In Situ</i> ALD-TEM System to Study Atomic Nucleation Phenomena - Enabled by Ultrathin Large Aspect Ratio Free-Standing Shell Structures

Today, Atomic Layer Deposition (ALD) sets the limits for achieving nanometer precision of thin, yet almost dense films. However, the initial growth process, determining possible film thinness, is poorly understood. A better understanding can be obtained with the help of in-situ characterization during film growth with high spatial and chemical resolution. Transmission Electron microscopy (TEM) would be a suitable and widely available technique to accomplish this objective. However, standard instruments have differing vacuum requirements than those necessary for ALD. During ALD, TEM detectors could be damaged as they are being exposed to corrosive volatile chemical compounds. Here we present a dedicated TEM holder design, where ALD deposition occurs inside a microchip containing a large area cavity surrounded by thin film Al2O3 membranes. These membranes act as windows for TEM characterization while decoupling the ALD process from the TEM environment. The microchip consists of longitudinal large overhang shell structures, themselves made by ALD and etched in an HF vapor etch processes. The set-up, which includes controlled heating, was tailored to ALD requirements, and passed a vacuum-pressure test. Post-mortem inspection of film growth on a silicon sample chip demonstrates the successful formation of an ALD Al2O3 film with 40 nm thickness inside the cavity. These results demonstrate the potential of the system to enable a range of experiments on growth phenomena that may lead to even thinner films and better control of interfaces than previously possible.

Microstructure evolution and performance degradation of sol-gel silica films induced by helium ion irradiation

Helium ion implantation in the sol-gel silica films was conducted at different fluences to study the impact of ion irradiation on defects, microstructures, wettability, optical properties and laser damage performance. The damage mechanism and performance degradation of the films induced by helium ion irradiation were analyzed. The cracks are observed after ion implantation and their transverse size increases but the depth decreases with the increase of ion fluence. At the same time, many small pores appear on the film surface and further expand at larger ion fluence. The Si–O–Si bond length and bond angle are reduced by helium ion implantation, thus leading to the densification of silica films. Helium ion implantation causes Si–Si bonds and Si–O bonds to break to form the defects such as ODCs and NBOHCs, further transforming into E′ centers. After ion implantation, the film surface changes from hydrophobic to hydrophilic due to the reduction of –CH3 groups, thus degrading the anti-pollution performance of the film. The significant decreases of laser damage thresholds of silica films are resulted from the increase of E′ centers and the expansions of cracks and pores. The results provide a reference to evaluate the lifetime of silica films used in high-power laser facilities, which is very important for the research of inertial confinement fusion.

Negatively correlated corrosion and stress corrosion cracking of Mg-Al-Mn-Ca based alloys

A negative correlation between corrosion and stress corrosion cracking (SCC) for Mg-Al-Mn-Ca-(Ce/Y) alloys is revealed. Specifically, high-level Al solute and trace Ce/Y alloying enhance the corrosion resistance via reducing Volta potential difference and forming dense corrosion product film. However, the compact film breaks severely during SCC, aggravating the initiation of cracks. Meanwhile, the numerous second phases facilitate H diffusion and adsorption, exacerbating the hydrogen enhanced decohesion in Ce/Y-containing alloy. The film rupture induced anodic dissolution and hydrogen enhanced decohesion dominate the SCC. This work shed light on fundamental understanding of the relationship between corrosion and SCC.

Effect of grain boundary engineering on corrosion behavior of 316 L stainless steel bipolar plate in proton exchange membrane fuel cells environment

This study illustrates the effect of grain boundary engineering (GBE) on the corrosion behavior of 316 L stainless steel (SS) in a proton exchange membrane fuel cells (PEMFCs) environment. It shows that the GBE increased the density of grain boundary and the coincidence site lattice (CSL) performes a better corrosion resistance, a preferential corrosion phase that the impurity elements are more likely biased at during the cast, the Random grain boundaries(RGBs) decreases. Furthermore, the texture on GBE2's closed-packed (111) plane reduces the surface atoms' dissolution velocity, thereby, decreasing the thermodynamic tendency to form dense corrosion films and nucleation kinetics. The above combined reasons lead to the lowest corrosion resistance of GBE2.

High growth rate magnetron sputter epitaxy of GaN using a solid Ga target

Magnetron sputter epitaxy (MSE) is a promising processing route for group-III nitride semiconductors, with the potential to enable high-quality and low cost GaN growth for widespread use. However, fundamental technological hurdles must be overcome to enable the adoption of MSE in industrial production. Here, we present a new UHV-compatible magnetron design with high-performance cooling, enabling high GaN growth rates at high growth temperatures using a solid Ga target. The magnetron is tested with a wide range of process parameters and a stable process is feasible while maintaining the solid state of the Ga target. High GaN growth rates of up to 5 μm/h are achieved at room temperature and a growth rate of 4 μm/h at high temperature, which is one order of magnitude higher compared to MSE with a liquid target. We grow GaN on c-plane sapphire substrates and show the impact of partial pressure ratio and target-to-substrate distance (TSD) on growth rate, film morphology and crystal quality of GaN films with scanning electron microscopy and X-ray diffraction. While the growth rate and film morphology are strongly impacted by the process parameter variation, the crystal quality is further impacted by the overall film thickness. For a 2 μm thick GaN film a full width at half maximum of X-ray rocking curve (ω-FWHM) of GaN 10 1‾ 1 reflection of 0.32° is achieved. We demonstrate a process window for growth of dense and smooth GaN films with high crystal quality using low N2 flow rates and high TSD. By introducing a 20 nm AlN nucleation layer prior to the growth of 390 nm GaN, the ω-FWHM of GaN 0002 reflection of 0.19° is achieved. The epitaxially grown crystalline structure is precisely examined by transmission electron microscopy.

Constructing a viscoelastic film for enhanced oil recovery via self-adsorption of amphiphilic nanosheets at oil-water interface

Immiscible liquid-liquid interfaces have widespread applications in drug delivery, oil-water separation, oil recovery, emulsion and foam stability, etc. Here, a dense viscoelastic interface film is constructed via the self-adsorption of amphiphilic molybdenum disulfide nanosheets at the oil-water interface, which has significant implications for enhanced oil recovery. The microscopic dispersion characteristics of amphiphilic nanosheets in water phase are characterized using Cryo-EM, and the adsorption regularities of amphiphilic nanosheets in horizontal and vertical directions of oil-water interface are also revealed. Besides the mechanical response and rheological properties of interface adsorption film are systematically studied. Experimental results demonstrate that the amphiphilic nanosheet can self-curl to form a single amphiphilic nanosheet with a size of 30 nm in the water phase as the amphiphilic nanosheets concentration is lower than 50 mg/L. When the amphiphilic nanosheets concentration reaches 100 mg/L, obvious water-phase aggregation behaviors happen. The amphiphilic nanosheets can reduce the oil-water interfacial tension from 18.47 mN/m to 0.27 mN/m by forming multilayer adsorption at the oil-water interface. The adsorption ratio of amphiphilic nanosheets from bulk phase to oil-water interface can reach 97.50 %. In addition, the oil-water interface adsorption film exhibits excellent elastic properties and higher strength because the amphiphilic nanosheets can form a planar network structure at the oil-water interface which can be also directly observed in microfluidic pores. The storage modulus and interface shear viscosity of interface adsorption film are 1.65 Pa and 1.38 mN·s/m, respectively. In theory, the required desorption energy of a single amphiphilic nanosheet from oil-water interface to bulk phase is deduced to be 587 KBT. This work is expected to provide amphiphilic molybdenum disulfide nanosheet as an effective candidate for enhanced oil recovery.

SiCw strengthened WC-Y2O3 composite and its electrochemical corrosion in aggressive medium

The mechanical properties and corrosion resistance of binderless tungsten carbide largely determine its performance and lifespan in complex industrial environments. Herein, WC-1Y2O3-xSiCw (x = 0, 0.5, 1, and 2 wt%) was prepared using the hot-press sintering. The mechanical properties of the composite, as well as the corrosion resistance of optimized mechanical properties in an aggressive medium (0.05 M H2SO4 and 1 M NaOH) were investigated. Results showed that SiCw could significantly increase mechanical properties of the composite, but excessive content (2 wt%) leads to whiskers aggregation and lower properties. The flexural strength and fracture toughness are all increased to varying degrees with whisker content. WC-1Y2O3-0.5SiCw possesses the optimal mechanical properties. The Vickers hardness, fracture toughness, and flexural strength are 2331.24 HV30, 8.59 MPa·m1/2, and 1727 MPa, respectively. Electrochemical tests show that the corrosion resistance of the WC-1Y2O3-0.5SiCw in H2SO4 is higher than that in NaOH solution, and its corrosion resistance in H2SO4 solution increases, but that of the NaOH solution decreases with exposure time. Detailed characterization demonstrated that a dense WO3 film forms in the H2SO4 solution, resulting in a flatter corrosion surface. In contrast, the WC phase in NaOH solution dissolves, thus leading to the accelerated corrosion rate.

Adjustable photovoltaic performance driven by polarization in molecular ferroelectrics

The photovoltaic effect driven by ferroelectric polarization shows great application potential in photovoltaic devices. Two-dimensional (2D) Ruddlesden-Popper perovskite molecular ferroelectric materials, which combine polarization and low band gap properties, occupy a promising position in this field. However, literature reports mostly focus on single crystal blocks, and film devices are rarely reported. In this paper, 2D EA4Pb3Br10 (EA=ethylammonium) molecular ferroelectrics are used as the absorption layers to prepare photovoltaic devices, and the photovoltaic performance of the devices is enhanced by polarization. Dense EA4Pb3Br10 films are prepared by immediately adding antisolvent propylene glycol methyl ether acetate when the spin coating rate reaches the maximum. Surprisingly, the photovoltaic device exhibits significant photovoltaic effects under AM1.5 (100 mW/cm2) illumination with VOC ∼ 1.042 V and JSC ∼ 438.02 μA/cm2, which is much higher than that of ordinary inorganic ferroelectrics. In addition, the photovoltaic performance has been greatly improved by applying an external electric field, reaching to the maximum VOC ∼ 1.087 V and JSC ∼ 489.12 μA/cm2. This indicates the potential application prospects of 2D EA4Pb3Br10 molecular ferroelectric films in photovoltaic devices.

Maximizing Roughness Factors in Oxide-Derived Copper Coatings through Electrodeposition Parameters for Enhanced Electrocatalytic Performance

The pursuit of novel techniques for obtaining dispersed copper-based catalysts is crucial in addressing environmental issues like decarbonization. One method for producing nanostructured metals involves the reduction of their oxides, a technique that has found widespread use in CO2 electroreduction. Currently, the intrinsic activities of oxide-derived copper electrocatalysts produced via different routes cannot be compared effectively due to the lack of information on electrochemically active surface area values, despite the availability of electrochemical methods that enable estimation of surface roughness for highly dispersed copper coatings. In this study, we aim to explore the potential of oxide-derived copper to achieve a high electrochemically active surface area by examining samples obtained from acetic and lactic acid deposition solutions. Our results revealed that Cu2O oxides had distinct morphologies depending on the electrodeposition solution used; acetate series samples were dense films with a columnar structure, while electrodeposition from lactic acid yielded a fine-grained, porous coating. The roughness factors of the electroreduced films followed linear relationships with the deposition charge, with significantly different slopes between the two solutions. Notably, a high roughness factor of 650 was achieved for samples deposited from lactic acid solution, which represents one of the highest estimates of electrochemically active surface area for oxide-derived copper catalysts. Our results highlight the importance of controlling the microstructure of the electrodeposited oxide electrocatalysts to maximize surface roughness.

G-C3N4 Boosting the Interfacial Compatibility of Solid-State Lithium-Sulfur Battery

The poor interfacial compatibility between solid electrolyte and lithium metal anode is one of the main obstacles to the development of solid lithium metal battery. Herein, the poly (1,3-dioxolane) (PDOL) polymer is combined with g-C3N4 powders to form a flexible and dense composite solid electrolyte film, which not only possesses high ionic conductivity of 3.7 × 10−4 S·cm−1, high ion migration number up to 0.86, and wide electrochemical stability window of 5.0 V, but also is helpful for inhibiting the growth of lithium dendrites to improve the interfacial stability of the lithium anode and close contact with cathode. The prepared S/g-C3N4-PDOL/Li battery exhibits good rate and cycle performances with a capacity of 550 mAh g−1 at 1 C, and 1150 mAh g−1 at 0.1 C with a capacity retention rate of 83% after 100 cycles. The dense Li3N layer generated by the reaction between g-C3N4 and Li gives g-C3N4/PDOL composite electrolyte a high inhibition ability of lithium dendrites. This composite solid electrolyte film with an interface modification function has good practical application prospects in lithium-sulfur batteries.