The fundamental understanding of activity differences between metal-rich transition metal phosphides in alkaline hydrogen evolution reaction (HER) remains limited. Here, Co2P and Ni2P nanoarrays grown on nickel foam (NF) were synthesized via hydrothermal and phosphidation methods. XRD, SEM, and XPS confirm phase-pure Co2P@NF (nanowires) and Ni2P@NF (nanosheet-assembled microspheres). In 1-M KOH, Co2P@NF exhibits a lower overpotential (78 mV) than Ni2P@NF (80 mV) at 10 mA cm−2, with Tafel slopes of 67.30 and 69.61 mV dec−1, indicating Heyrovsky-dominated kinetics. Co2P@NF also shows a larger electrochemical surface area (3.6 cm2) and lower charge transfer resistance (1.2 Ω). Density functional theory (DFT) reveals that Co2P has a higher density of states near the Fermi level and more optimal hydrogen adsorption free energy (− 0.66 eV vs. − 0.78 eV for Ni2P), explaining its superior intrinsic activity. This study provides insights into designing efficient non-noble metal phosphide electrocatalysts.

Vanadium redox flow batteries (VRFBs) are regarded as an ideal candidate technologies for large-scale energy storage systems because of their advantages of strong scalability and long cycle life. However, its practical application is limited by the key problem of slow redox reaction kinetics on the electrode surface. In this study, a simple, low-cost and non-polluting method was used to etch the graphite felt to regulate the surface characteristics of the graphite felt electrode. Through the synergistic reaction of oxide and graphite felt at high temperature, a porous carbon layer structure with high roughness was constructed on the electrode surface, and oxygen-containing functional groups. The results of SEM, XPS and Raman tests revealed that as the number of oxygen-containing functional groups on the modified electrode increased, the specific surface area increased by approximately 329

Layered titanium lithium ion-sieve (H2TiO3, HTO) is considered among the most promising adsorbents in liquid lithium extraction technology because of its environmental friendliness, low cost and high H/Ti ratio. In this work, the precursor of Li2TiO3 (LTO) was synthesized by co-doping Zr and F with a high-temperature solid phase method through density functional theory (DFT) calculations and corresponding experiments, and then the doped ion sieve (Zr/F-HTO) is obtained by elution with H2SO4. The specific surface area of Zr/F-HTO is up to 131.64 m2/g, and the adsorption capacity is 68.66 mg/g. The adsorption behavior of Zr/F-HTO on Li+ is consistent with the Langmuir adsorption thermodynamic model and pseudo-second-order kinetic model. In addition, batch experiments revealed that Zr/F-HTO exhibits good lithium selectivity in simulated submerged lithium mother liquor, and the capacity retention rate is as high as 97.7% after five "adsorption-desorption" cycles. The simple economic calculation shows that the adsorbent has good industrial application potential. Therefore, the proposed Zr/F-HTO provides an economical and effective scheme for the efficient extraction of lithium from submerged lithium mother liquor.

In this work, the granulation of titanium lithium-ion sieves and its application in the recycling of waste lithium-ion batteries were studied. To address the problems of poor permeability and fluidity of lithium-ion sieve powder and low circulation efficiency, modified powder Zr/F-HTO was granulated by using a styrene acrylic emulsion and ethyl cellulose as binders. A comparison of the morphology, specific surface area, and adsorption properties of the granular lithium-ion sieve obtained from the two binders revealed that the granular lithium-ion sieve (SA-Zr/F-HTO) bonded with the styrene acrylic emulsion has a more porous surface structure and a larger specific surface area, and thus has a greater adsorption capacity. The results also show that the adsorption process of SA-Zr/F-HTO conforms to the Langmuir adsorption thermodynamic model and pseudo-second-order kinetic model, indicating that the adsorption process is monolayer chemisorption. In addition, SA-Zr/F-HTO showed excellent lithium selectivity and good cycle stability in simulated lithium-containing mother liquor. The results of column adsorption experiments show that SA-Zr/F-HTO has a long penetration time and high adsorption efficiency, which is suitable for continuous operation and provides an effective method for the efficient recovery of lithium in waste lithium-ion batteries.

Vanadium redox flow batteries (VRFBs) are considered a highly promising large-scale energy storage technology due to their long lifespan, high safety, large capacity, and high efficiency. In practical applications, pentavalent vanadium in the positive electrolyte of vanadium batteries is prone to precipitation under conditions of high temperatures and concentrations, reducing the energy density and cycle life of VRFBs. Therefore, choosing appropriate additives to improve the stability of pentavalent vanadium ions is crucial. This study researched the effects of two hexahydric alcohols (inositol and galactitol) as electrolyte additives on the performance of vanadium-positive electrolyte through X-ray diffraction (XRD), Raman spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge tests. The results show that both inositol and galactitol can improve the electrochemical performance of vanadium-positive electrolyte. At a current density of 80 mA cm−2, the energy efficiency of the battery groups with inositol and galactitol added increased by 1.24

In the domain of hydrogen evolution reaction (HER) cathode catalysts, MXenes-containing materials are considered to possess considerable potential owing to their unique two-dimensional layered architecture. Conversely, the production processes of these materials, together with the selection of diverse nitrogen doping strategies and the underlying mechanisms, remain subjects requiring further investigation. This experiment employed the molten salt method for the synthesis of MXenes. This approach is beneficial as it effectively mitigates the influence of fluorine groups on the electrochemical characteristics of MXenes. A study was conducted on the effects of doping with two distinct nitrogen sources: urea and lithium nitride. The microstructures and electrochemical characteristics were analyzed to ascertain the most effective preparation and nitrogen doping methods. The Ti3AlC2 precursor was specifically etched with CoCl2 in a eutectic salt solution of KCl and LiCl to produce Ti3C2. Subsequently, lithium nitride was selected as the nitrogen source, resulting in the synthesis of MXenes with enhanced hydrogen evolution reaction performance. The studied HER cathode material exhibited a distinctly defined layered structure with significantly increased interlayer gap. This led to an increased surface area and a higher density of active sites. The electrochemical test findings indicated an overpotential of 82 millivolts at a current density of 10 milliamperes per square centimeter, with a Tafel slope of 120.4 millivolts per degree. The electrochemical impedance spectroscopy (EIS) analysis revealed that the series resistance (Rs) is 1.571 Ω, indicating a low value. The charge transfer resistance (Rct) was measured at 78.56 Ω, corroborating the superior performance. The material exhibited exceptional stability throughout the testing phase.

Alkaline water electrolysis is an important method for sustainable hydrogen production, and exploring efficient cathode materials is of utmost importance. In this study, Ni-Mo-P/NF hydrogen evolution cathode materials for alkaline water electrolysis-based hydrogen production were fabricated by electrodeposition method. During this process, with nickel foam (NF) as the substrate, the composition of the plating solution is nickel sulfate, sodium molybdate and sodium hypophosphite. The ions of Ni2+, MoO42− and H2PO2− in the plating solution were reduced and co-deposited on the surface of the foamed nickel, forming a Ni-Mo-P alloy coating. Furthermore, the electrode surface presented a honeycomb-like structure. The Ni-Mo-P/NF cathode electrode material exhibited excellent electrocatalytic performance, as demonstrated by electrochemical performance tests. In a 1 M KOH electrolyte, the hydrogen evolution reaction (HER) has a relatively low overpotential η10 of 0.109 V, with a Tafel slope of 121.8 mV/dec; the AC impedance Rct is 56.47 Ω; the electrochemical specific surface area is 87.6 cm2. This outstanding catalytic activity is attributed to the synergistic effect among Ni, Mo and P. Mo modulates the electronic structure of Ni, enhancing the adsorption and dissociation of water molecules, whereas P increases the overall catalytic efficiency of the material. This study provides valuable references for the development of highly active nonmetal-based cathode materials in the alkaline water electrolysis field

The one-step direct current deposition method has been investigated for the preparation of the Ni-Mo alloy and Ni-Mo-W alloy coatings on nickel-foam substrates. Under optimal conditions, binary alloy and ternary alloy electrode materials with excellent properties were prepared, and the corresponding microstructures and electrochemical properties were studied and compared. Scanning electron microscopy was used to characterize the morphology of the Ni-Mo-W/NF porous hydrogen evolution electrode. Compared with those of the Ni-Mo binary coating, the particles on the surface of the ternary coating were more tightly packed, and some of them were also stacked into a double layer; thus, the electrode had more active sites, and the surface of the coating was almost seamless. Under the test conditions of a 1-M KOH solution at room temperature, the hydrogen evolution overpotential, η10, of the Ni-Mo/NF porous hydrogen evolution electrode and the Ni-Mo-W/NF porous hydrogen evolution electrode were 0.128 V and 0.119 V, respectively. The ternary alloy deposition coating had a better electrocatalytic performance for hydrogen evolution. The Tafel slopes, Rct resistances, and the specific active surface areas of the Ni-Mo/NF binary porous electrode and the Ni-Mo-W/NF ternary porous electrode were 135.6 mV/dec and 128.3 mV/dec, 84.13 Ω and 69.23 Ω, and 23.2 cm2 and 63 cm2, respectively. The Ni-Mo-W/NF porous hydrogen evolution electrode had better long-term stability, and the changes in the hydrogen evolution overpotential value were < 10

Using ammonium metavanadate as the raw material, vanadium trioxide was prepared by using ammonia gas produced by the self-thermal decomposition of ammonium metavanadate and external carbon powder as the reducing agent in a tube furnace. The effects of the reaction temperature, reaction time, and carbon content on the purity of vanadium trioxide were investigated. The results show that high-purity vanadium trioxide with a V content higher than 67

Vanadium dioxide (VO2) exhibits reversible thermal phase transitions, with a transition temperature near room temperature, making it a promising functional material for phase change applications. However, VO2 thin films face challenges such as a trade-off between luminous transmittance and solar modulation capability, as well as a phase transition temperature that is too high for practical use. This study addresses these issues by synthesizing Eu-doped VO2 thin films using a novel hydrothermal-assisted electrophoretic approach. The impact of Eu doping on the structural, morphological, thermal, optical, and mechanical properties of VO2 films was comprehensively analyzed. Key findings reveal that Eu doping increases lattice spacing and results in a flower-like microstructure. At different Eu doping concentrations, the phase transition temperature has decreased, and the luminous transmittance and solar modulation capability have increased. In addition, the hardness and elastic modulus of the film have both been improved compared with the undoped thin film.

The development of a hydrogen evolution catalyst with both catalytic activity and stability is critical for hydrogen production from electrolytic water. Herein, a V-based porous alloy was prepared via high-energy ball milling and solid-state sintering. Then, the V-based porous alloy was modified with a Ni-Cu-Mo ternary alloy coating by direct current electrodeposition to obtain a composite hydrogen evolution cathode with high hydrogen evolution activity. The substrate has a certain hydrogen storage capacity combined with a high-activity Ni-Cu-Mo coating. The composite hydrogen evolution cathode exhibited high electrocatalytic activity toward the HER. It can afford a lower overpotential of 93 mV and a smaller Tafel slope of 97.4 mV/dec with a current density of 10 mA/cm2 in 1.0 M KOH. The composite hydrogen evolution cathode demonstrated outstanding stability after 2000 cycles and good durability after intermittent electrolysis for 20 h. Hydrogen protons can protect the components of the cathode composite from dissolution during discontinuous constant potential electrolysis. The composite hydrogen evolution cathode also exhibited a strong catalytic capacity for hydrogen evolution during intermittent electrolysis under alkaline conditions.

Ce-doped V2O5 thin films on FTO conductive glass substrates were prepared by electrodeposition-assisted sol-gel method. The influences of Ce doping on the phase, surface morphology and optical properties of V2O5 thin films deposited on FTO substrates were examined. The results revealed that the films have good crystallinity and high purity. Ce doping is slightly helpful to the increase of grain size of the films. With 1.0 at.

A facile and one-step direct-current electrodeposition method was employed to synthesize Ni-Mo-W coatings on nickel foam substrates with different electrochemical parameters. The corresponding microstructure and electrochemical characteristics were investigated for the optimized process conditions. A considerably rough surface and numerous spheres on the coatings were observed. X-ray diffraction analysis demonstrated that the Ni-Mo-W alloy had broadened diffraction peaks, indicating the formation of a nano amorphous structure. It also presented a meticulous cubic Mo-Ni substitutional solid solution. Electrochemical measurements revealed that a lower overpotential of only 122 mV at 0.08 mA·cm−2 and long-term stability can be achieved. A smaller Rs of 0.2 Ω and a lower Rct of 7.236 Ω at the electrode/electrolyte interface were obtained by electrochemical impedance analysis. According to first-principles calculations, the formation energy for creating a solid solution with W atoms is negative, with a value of -6.386 eV, thereby confirming the enhanced stability of the alloy.

We present a simple method for producing SiO2-modified LiNi0.5Mn1.5O4 (LNMO) cathode materials. Manganese carbonate was directly mixed with nickel nitrate and lithium hydroxide, and a spherical structure LNMO cathode material was prepared by two-step calcination, then ethyl orthosilicate and LNMO powder were simply mixed in solid and liquid phases to prepare SiO2-coated LNMO material. The effect of SiO2 coating on the structure of LNMO was studied by diffraction of X-rays, scanning electron microscope (SEM), transmission electron microscope (TEM), and thermogravimetric analysis and differential scanning calorimetry. An amorphous SiO2 coating layer developed on the surface of the LNMO particles in the modification and this could alleviate the strike of hydrogen fluoride (HF) caused by electrolyte decomposition as well as the development of a solid electrolyte interphase. The electrochemical performance of the coated material was as follows: when the amount of SiO2 was 0 wt%, 1 wt%, 2 wt%, and 3 wt%, the initial discharge capacity of the sample was 98.2, 84.1, 101.3, and 89.8mAh/g, respectively. After 50 charge-discharge cycles, the capacity retention rates are 92.7%, 66.8%, 97.9%, and 93.8%, respectively. The cyclic stability of the samples can be significantly improved when the SiO2 coating amount is 2 wt% and 3 wt%, indicating that SiO2 coating can not only improve the discharge-specific capacity of the material but also improve its cyclic stability.

针对锂云母提锂废液中稀碱金属铯、铷难以高效分离现状,为实现深度萃铯脱铷目的,通过热力学分析萃取过程中铯与t-BAMBP结合形成的分子簇稳定形态,探索提锂废液中低浓度铯萃取机理.结果表明:分子簇的稳定性与t-BAMBP和Cs+结合的数量有关,其中3t-BAMBP-2Cs型分子簇的形成热低,可稳定存在于有机相内.在t-BAMBP+磺化煤油+环己烷萃取体系中,最佳试验条件下经六级萃取二级洗涤,铯的萃取率为99.52％,铷的洗脱率为96.69％,铷、铯得到较好的分离.

采用复合盐焙烧?水浸工艺从锂云母中提取锂、铷、铯,研究了焙烧工艺参数及浸出工艺参数对锂、铷、铯浸出率的影响.结果表明,锂云母精矿焙烧时,复合盐焙烧效果优于单一盐添加剂,CaCl2+Na2 CO3组合添加剂具有焙烧时氯气排放少、焙烧矿浸出效果好等优点.从锂云母中回收锂、铷、铯,较佳的焙烧?浸出工艺条件为:CaCl2+Na2 CO3组合为焙烧添加剂,锂云母精矿:CaCl2:Na2 CO3(质量比)=1:0.5:0.2,锂云母精矿焙烧温度900℃、焙烧时间2 h,对焙烧矿进行室温水浸,浸出时间1 h、液固比2:1,此时锂、铷、铯浸出率分别为86.64％、92.58％、85.37％.含锂浸出液经2次调节pH值净化除钙,升温至95℃后加入饱和Na2 CO3溶液,结晶得到碳酸锂,样品纯度为99.08％,产品纯度及杂质含量达到一级碳酸锂标准.沉锂母液采用溶剂萃取法分离铷、铯,铯萃取率达到99％以上,铷洗脱率达到96％左右.

重金属冶炼烟气制酸的废催化剂杂质组成相对复杂,为获得此类废催化剂综合回收钒、钾、锌工艺的优化条件,对直接湿法浸出工艺钒、钾、锌浸出率的影响因素进行了试验研究.通过单因素试验,系统研究了浸出剂质量分数、液固比、反应温度、反应时间对钒、钾、锌浸出率的影响,其次对废催化剂和浸出渣的化学成分及物相进行了分析对比.结果表明,浸出的最佳工艺条件为:硫酸质量分数8％、液固比2∶1、浸出温度70℃、浸出时间1.5 h,钒、钾、锌的浸出率分别达93.58％、85.43％、99.31％,优于传统焙烧法.

提出了一种以FeO-SiO2-Al2O3-CaO渣体系为基础的废旧电路板还原熔炼工艺,从减少渣中金属损失及控制性能角度,对渣成分及结构进行调控,研究了熔剂添加量、熔炼时间、熔炼温度、炉渣组成成分对金属回收率的影响.结果表明,在熔剂添加量为原料质量30％、熔炼温度1450℃、熔炼时间75 min、FeO/SiO2比为1、渣中CaO含量8％条件下,废旧电路板中Cu、Sn回收率分别为91.98％、86.30％,贵金属Au、Ag、Pt在合金相中含量分别可达67.41 g/t、1020.74 g/t、54.75 g/t.以该渣系为基础还原熔炼废旧电路板的工艺是可行的.

采用水热合成结合高温热处理制备了VO2粉体,研究了Zr元素掺杂对VO2结构及相变性质的影响.结果表明:掺杂Zr元素会对VO2结构产生影响,Zr4+可以占据V4+晶格点阵位置,形成有限固溶体,从而增大VO2的晶胞参数,不同浓度Zr掺杂试样,仍呈VO2单斜相结构.由于掺杂导致的晶格变形,阻止了颗粒的聚集,因此Zr添加具有一定的细化晶粒作用.DSC曲线测试表明,Zr掺杂可以降低VO2(M)的相变温度,掺杂浓度为6％(原子百分比,下同)时,相变温度可由未掺杂的69.9℃降到61.1℃,Zr掺杂试样相变前后的红外透射率变化也较大,达到30％ 以上.

采用水热合成法制备了VO2粉体,研究了水热条件和Y、La、Ce等元素掺杂对VO2结构及相变温度的影响.结果表明:水热反应时间和温度对VO2晶粒生长影响显著,190℃保温72 h条件下制备的VO2粉体结晶度较好.稀土离子掺杂对VO2粉体成型和相变温度都有影响,其中Y掺杂能起到明显的细化晶粒作用,同时能使VO2相变温度由未掺杂时的68.3℃降到61.6℃;La和Ce的掺杂效果相近,都会对VO2主体结构产生一定破坏,虽然能起到一定降低相变温度的作用,但相转变效果较差.