Materials Chemistry Commons^™

Intrinsic Kinetic Properties Of Ternary Material For Lithium Ion Batteries Assessed By Single Particle Microelectrode, Yi-Min Wei

Journal of Electrochemistry

Electrochemical performances such as capacity, rate, cycle and thermal stability of the nickel (Ni), cobalt (Co) and manganese (Mn) ternary cathode material, LiNi_xCo_yMn_zO₂ (x + y + z = 1), are significantly influenced by the proportion of Ni, Co, and Mn elements. To obtain higher specific capacity, LiNi_0.6Co_0.2Mn _0.2O₂ (NCM622) and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) with high amounts of Ni element were employed for the lithium ion batteries. By now, many studies have been focusing on the thermal and cycling stabilities of …

Effects Of Carboxylic Acids On Structure And Performance Of 10% Vanadium Modified Li2Fesio4/C Composites, Xue-Xia Wei, Jia-Qi Huang, Shi-Yang Liu, Xuan Cheng, Ying Zhang

Journal of Electrochemistry

The carbon coated 10% vanadium modified lithium iron silicate (Li₂Fe_0.9V_0.1SiO₄/C) composites were prepared by sol-gel method to form precursor and followed by solid state reaction. Effects of different carboxylic acids, namely, citric acid, acetic acid and oxalic acid, on the crystal structures, surface morphologies, interfacial characteristics and electrochemical properties of the composites were systematically investigated. It was found that a mixed P2₁ and Pmn2₁ phase was formed with the major impure phase of iron (Fe) and minor impurity of lithium silicate (Li₂SiO₃). The initial discharge capacities …

Deposition Mechanism And Coating Characterization For The Trivalent Chromium Electrodeposition In Sulphate Electrolyte, Hui Yan, Shuai-Shuai Huang, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were used to study the electrodeposition mechanism of trivalent chromium on a copper electrode in the novel sulphate electrolyte for thick trivalent chromium plating. The thickness, morphology, composition, microhardness, and structure, as well as the corrosion resistance in 3.5wt% NaCl solution of the trivalent chromium coatings were investigated by X-ray fluorescence gage, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), microhardness tester, X-ray diffraction (XRD) and Tafel curve measurements. The results showed that the electrodeposition of trivalent chromium involved two consecutive one electron reduction steps. The first step, Cr³⁺ + e …

Preparation And Electrocatalytic Activity Of Nitrogen-Doping Tungsten Carbide Catalyst, Pian-Pian Yang, Li-Zhen Huang, Ying-Ying Li, Mei-Qin Shi, Chun-An Ma

Journal of Electrochemistry

Tungsten carbide (WC) is a promising electrocatalyst, however, its electrocatalytic activity is far inferior to Pt and Pt-group metal. In this work, nitrogen-doping tungsten carbide (WN|WC) catalysts with a nanoplate morphology were prepared via the tungsten nitride (WN) as the precursor and sodium tungstate as the tungsten source. The SEM and TEM results indicated that carbon atoms entered into the WN lattice to form the hexagonal close packed WC phase. In this way, an atomic scale heterostructure involving the closely linked interfaces between WN and WC was created . The XRD data confirmed that the cubic crystal structure of WN …

Electrodeposition Of Cigs Thin Film With Special Structure Using Laser Etching Template, Jin-Zhi Yu, Ye Lian, Jin-Qiu Zhang, Pei-Xia Yang, Mao-Zhong An

Journal of Electrochemistry

Copper indium gallium selenide (Cu_1.00In_xGa_1-xSe_2.00, CIGS) thin film solar cells have a wide application in semiconductor thin film batteries. The CIGS absorbing layer is the key of the thin film solar cell material. Therefore, it is of theoretical and practical significance to carry out researches in CIGS thin films. In this work, the CIGS thin films with special structures were prepared by using laser etching template. The copper thin film was firstly electrodeposited in aqueous solution with Laser etching template. The influences of temperature, current and concentration of copper sulfate on morphology …

Preparation And Properties Of Nanocrystalline Nickel By Pulse Electrodeposition On Glassy Carbon, Ya-Li Zhang, Ming-Xian Zhang, Teng-Da Guo, Yan-Jie Zhao, Sheng-Xue Yu

Journal of Electrochemistry

Nanocrystalline nickel exhibits electrocatalytic activity for methanol. In this work, nanocrystalline nickel coating has been obtained by using the double pulse method on glassy carbon materials surface. The influence of pulse conditions on the grain size of nanocrystalline nicke was studied. The concentrations and compositions of the plating bath were 300 g·L^-1 NiSO₄·6H₂O，45 g·L^-1 NiCl₂·6H₂O，40 g·L^-1 H₃BO₃，5 g·L^-1 C₇H₅NO₃S，and 0.05 g·L^-1 C₁₂H₂₅NaO₄S. The optimal pulse process parameters including the average pulse …

Applications Of Electrospinning In Lithium-Air Batteries, Yue Fu, Jin Wang, Hai-Yang Yu, Jing-Hua Tian, Rui-Zhi Yang

Journal of Electrochemistry

Lithium-air batteries have received increasing attention as the “ultimate batteries” due to their extremely high theoretical capacity and environment friendly. However, there are still many obstacles hindering the wide applications of the lithium-air batteries owing to the limitations of large charge-discharge over-potentials, poor Columbic efficiency and cycling performance. Exploring of high-efficiency, low-cost and eco-friendly catalysts is one of the vital issues for lithium-air batteries. Meanwhile, electrospinning techniques have been under substantial developments due to its simple fabrication process, high efficiency and production. This paper reviews the recent progresses in fabrications of various novel catalysts for lithium-air batteries with electrospinning techniques, …

Preparation And Characterization Of Titanate-Phosphate Passivation Film On Tinplate, Zi-Yu Wang, Ming-Hao Wang, De-Yu Li, Ning Li

Journal of Electrochemistry

A passivation film was prepared on tinplate surface with a composite passivating agent made of titanate and phosphate. The surface morphologies, chemical compositions and corrosion resistances of the passivation films were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), salt spray test, Tafel polarization measurement and electrochemical impedance spectroscopy (EIS). The results were compared with those films untreated and treated with titanate or phosphate passivation. It was shown that the titanate and phosphate passivation film was mainly composed of Ti₃(PO₄)₄·nH₂O and TiO₂. The finely crystallized surface could seal …

Synthesis And Electrochemical Properties Of Nickel-Rich Cathode Material Lini0.6Co0.2Mn0.2O2 With High Initial Coulombic Efficiency, Xiao-Yun Guan, Chao-Yu Hong, Jian-Ping Zhu, Wei-Li Wang, Yi-Xiao Li, Yong Yang

Journal of Electrochemistry

Nickel-rich cathode materials LiNi_0.6Co_0.2Mn_0.2O₂（NCM622）were synthesized by a co-precipitation-solid state sintering method at different temperatures. The structure, morphology and electrochemical performance of the as-prepared materials were investigated by X-ray powder diffraction (XRD) /Rietveld refinement, scanning electron microscope (SEM) and electrochemical experiments. It is found that NCM622 calcined at 800 ℃ showed the lowest degree of cation disorder (~1.97%) with a high initial Coulombic effiency of 92.2% and the capacity retention of 81.4% after 100 cycles.

Preface For Special Issue On Electroplating And Surface Finishing, Mao-Zhong An

Journal of Electrochemistry

Electroplating and surface finishing, which belongs in the category of electrochemical industry, is an ancient science having a long history and playing an important role in many fields of the national economy, for instance, machinery manufacturing, power electronics, instrumentation and aerospace. However, researches and developments in electroplating and surface finishing have been significantly impeded due to the resources constraints and environmental concerns. It is, therefore, urgent for the general electroplating scientists and engineers with unremitting efforts to develop new technologies and new processes to meed the new demands in order to relieve the pressures in resources and environments.
　　The disciplinary …

Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles, Grant C. Bleier

Chemistry and Chemical Biology ETDs

A novel synthetic method for the production of highly magnetic, low size-dispersity nanoparticles through reversible magnetic agglomeration is introduced and studied in detail. Initially, a weakly coordinating surfactant (3-octadecyl-2,4-pentanedione) is employed to produce a wide range of nanoparticle sizes ranging from 8 to 20 nm in diameter. The kinetics faced in these reactions by cheap and widely available iron complex precursors can be avoided in this method with the introduction of thermodynamic control, which occurs in the form of a magnetic precipitation event that essentially halts nanoparticle growth. Utilizing this synthetic method, the length of the alkyl chain on the …

Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li

Dissertations, Theses, and Capstone Projects

For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO₂ electrochemical reduction reaction (CO₂ERR). The Faradaic efficiencies (FE) of CO and CH₄ formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH₄ formation of 29% and 0.76%, respectively. It was found that the overall performance in CO₂ERR dramatically increased upon the reduction pretreatment of the carbons in N₂-saturated electrolyte before the CO₂ reduction process. The pretreated carbon showed the maximum FE of CO …

Solution Deposition Of Conformal Gold Coatings On Knitted Fabric For E-Textiles And Electroluminescent Clothing, Tricia Carmichael, Yunyun Wu, Sara S. Mechael, Yiting Chen

Chemistry and Biochemistry Publications

The vision for wearable electronics involves creating an imperceptible boundary between humans and devices. Integrating electronic devices into clothing represents an important path to this vision; however, combining conductive materials with textiles is challenging due to the porous structure of knitted textiles. Stretchability depends on maintaining the void structure between the yarns of the fabric; filling these voids with conductive materials stiffens the textile and can lead to detrimental cracking. The authors demonstrate the solution-based metallization of a knitted textile that conformally coats individual fibers with gold, leaving the void structure intact. The resulting gold-coated textile is highly conductive, with …

Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel

LSU Doctoral Dissertations

Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), …

Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal

FIU Electronic Theses and Dissertations

With the ever-advancing technology, there is an incessant need for reliable electrochemical energy storage (EES) components that can provide desired energy and power. At the forefront of EES systems are electrochemical capacitors (ECs), also known as supercapacitors that typically have higher power and superior cycle longevity but lower energy densities than their battery counterparts. One of the routes to achieve higher energy density for ECs is using the hybrid EC configuration, which typically utilizes a redox electrode coupled with a counter double-layer type electrode.

In this dissertation, both scale-up (coin-cell type) as well as scale-down (on-chip miniaturized) hybrid ECs were …

New And Optimized Green Synthesis Of Silver Nanoparticles Using Mullein, Marisa Thompson, Cuong Nguyen, Anna Holmes

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Modification Of Wheat Gluten For Improvement Of Binding Capacity With Keratin In Hair, Shukun Wang, Danyang Meng, Sisi Wang, Zhong Zhang, Ruijin Yang, Wei Zhao

Department of Food Science and Technology: Faculty Publications

In this study, enzymatic hydrolysis and cationization with epoxypropyldodecyldimethylammonium chloride of wheat protein, an economic protein complex containing great amount of disulfide bonds, were conducted to improve properties such as solubility and disassociation behaviour for recovery of damaged hair when used in shampoo. The optimal conditions for enzymatic hydrolysis were pH 8.2, 55°C with Alcalase for 60min. After the selected hydrolysis, the degree of hydrolysis, nitrogen solubility index, foaming capacity index, foam stability index, emulsifying activity index and emulsion stability index of hydrolysate with 58.71% of shortchain peptides (less than 1000 Da) were 8.81%, 39.07%, 225%, 56.67%, 9.62m² g …

Abnormal Phase Transition Between Two-Dimensional High-Density Liquid Crystal And Low-Density Crystalline Solid Phases, Wenbin Li, Longjuan Kong, Baojie Feng, Huixia Fu, Hui Li, Xiao Cheng Zeng, Kehui Wu, Lan Chen

Xiao Cheng Zeng Publications

Some two-dimensional liquid systems are theoretically predicted to have an anomalous phase transition due to unique intermolecular interactions, for example the first-order transition between two-dimensional high-density water and low-density amorphous ice. However, it has never been experimentally observed, to the best of our knowledge. Here we report an entropy-driven phase transition between a high-density liquid crystal and low-density crystalline solid, directly observed by scanning tunneling microscope in carbon monoxide adsorbed on Cu(111). Combined with first principle calculations, we find that repulsive dipole–dipole interactions between carbon monoxide molecules lead to unconventional thermodynamics. This finding of unconventional thermodynamics in two-dimensional carbon monoxide …

Structural Evolution Of Gold-Doped Bismuth Clusters AubiN– (N = 4−8), Seema Pande, Tian Jian, Navneet S. Khetrapal, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The structures of gold-doped bismuth clusters, AuBi_n⁻ (n = 4−8), are investigated through a joint photoelectron spectroscopy and density functional theory (DFT) study. Well-resolved photoelectron spectra are obtained at several photon energies. Global minimum searches coupled with DFT calculations yield low-lying structures, whose relative energies are further evaluated by single-point energy calculations at the CCSD(T) level of theory. Vertical detachment energies are calculated with the inclusion of spin−orbit effects to compare with the experimental data. Three-dimensional structures are found to be dominant in this size range, while a planar low-lying isomer is observed only for AuBi_{4 …}

Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts

Chemistry Publications

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing …