Physical Chemistry Commons^™

An Stm Study On The Structure Of Pt(100)/Ionic Liquid Omipf6 Interface, Jin Peng, Mian-Gang Li, Li-Qiang Xie, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

Potential-dependent structures of Pt(100)/ionic liquid 1-methyl-3-octylimidazolium hexafluorophosphate (OMIPF₆) interface have been studied by electrochemical scanning tunneling microscopy (ECSTM). The cation OMI⁺ forms ordered structure on Pt(100) surface, which exists in a potential region of about 1.2 V. When the potential is more negative than -0.6 V, it can be seen that the ordered structure transforms to disordered structure. When the potential shifts positively to +0.6 V, the desorption of cations OMI⁺ occurs, which indicates that strong electrostatic repulsion is needed to overcome chemical interaction between OMIPF6 and Pt(100) surface, leading to the desorption. The above results …

Lithium Plating Identification From Degradation Behaviors Of Lithium-Ion Cells, Jian-Bo Zhang, Lai-Suo Su, Xin-Yu Li, Hao Ge, Ya-Kun Zhang, Zhe Li

Journal of Electrochemistry

Lithium plating has huge impact on the lifetime and safety of lithium-ion cells. It is, therefore, necessary to identify lithium plating. In this study, the accelerated stress tests of lithium-ion cells were conducted under different conditions with multi-stress loads. Based on the different effects of the two major aging mechanisms, namely, SEI (Solid Electrolyte Interface) layer growth and lithium plating, on the degradation behaviors, two lithium plating identification methods of resistance-capacity plot and Arrhenius plot were employed. The experimental results revealed that the two identification methods are highly consistent with each other. Furthermore, the origins of capacity loss were distinguished …

Micro/Nano-Structured Electrode Materials For Sodium-Ion Batteries, Shuang Yuan, Yun-Hai Zhu, Sai Wang, Tao Sun, Xin-Bo Zhang, Qiang Wang

Journal of Electrochemistry

Sodium has similar physics and chemical properties to lithium, alternatively, sodium (Na)-ion batteries have again aroused a great deal of interest recently, particularly for large-scale stationary energy storage applications due to the practically infinite sodium resources and low cost. However, the technics and materials for Na-ion batteries are immature. Therefore, development of advanced anode and cathode materials for Na-ion batteries is urgently desired but remains a great challenge. This paper briefly reviews some recent progresses in this field, addressing the morphology effects, as well as functions of carbon composite materials toward Na-ion batteries. Several electrode materials with micro/nano-structures based on …

Construction And Sodium Storage Performance Of Complex One-Dimensional Nanomaterials, Yuan-Jie Zhang, Wei Li, Xuan-Peng Wang, Chao-Jiang Niu, Li-Qiang Mai

Journal of Electrochemistry

One-dimensional nanomaterials have been widely studied in energy storage and conversion fields because of their unique structure and physicochemical properties. Sodium-ion batteries are highly promising and attractive for large-scale energy storage due to the truly abundant sodium resources and low cost. With the growing demand of energy and deepening of research, the evolution of structures and properties of one-dimensional nanomaterials are also experiencing from simplicity to complexity and from ordinary to excellence. Therefore, constructing complex superior one-dimensional nanomaterials has become one of the hotspot in energy storage. Based on the new advance in this field and Mai group’s work, this …

Research Progress In Cycle Stability Of Silicon Based Li-Ion Battery Anodes, Ze-Liang Guo, Hui Wu

Journal of Electrochemistry

Silicon(Si), with the highest specific capacity currently known, is a promising anode material for Li-ion battery. However, in the charging and discharging process, with Li atoms inserting into and breaking out of the Si crystal lattices, the Si anode undergoes enormous volume expansion and contraction, ending in pulverization. The fact that the specific capacity of bulk Si anodes drop quickly is a challenging problem. In this review, we summarize recent progresses in Si anode. We concern about the nanostructure of silicon, cooperation of silicon with other additives and macrostructure design of anodes. We discuss strengths and shortcomings of different methods, …

Electrochemical Performance Of Crystalline Li12Si7 As Anode Material For Lithium Ion Battery, Ya-Xiong Yang, Rui-Jun Ma, Ming-Xia Gao, Hong-Ge Pan, Yong-Feng Liu

Journal of Electrochemistry

Crystalline Li₁₂Si₇ is successfully synthesized by heating the mixture of LiH and Si with a molar ratio of 12:7, which avoids the huge difference of the melting points between Li and Si. The electrochemical performance and lithium storage mechanism of the as-prepared Li12Si7 are studied in this work. It is found that only a change in cell volume takes place without a phase change during the lithiation/delithiation of Li₁₂Si₇ at a voltage range of 0.02 ~ 0.6 V, exhibiting a solid-solution lithium storage mechanism. Such a lithium storage process effectively retards the volume effect …

Continuous Synthesis And Condition Exploration Of Precursor Ni1/3Co1/3Mn1/3(Oh)2 Ternary Cathode Material, Zhi-Jun Jiang, Ya-Li Zhang, Qian Wang, Hui Zhang

Journal of Electrochemistry

Commercial LiNi_1/3Co_1/3Mn_1/3(OH)₂ ternary material is generally prepared by a combination of co-precipitation and solid state reaction method. The particle size distribution and morphology of Ni_1/3Co_1/3Mn_1/3(OH)₂ precursor have a great impact on the electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂. In this work, the precursor Ni_1/3Co_1/3Mn_1/3(OH)₂ ternary cathode material was prepared by co-precipitation method with MnSO₄, NiSO₄, and CoSO₄ as raw materials, NaOH as a precipitating agent and NH_{3 …}

Research And Application Of Key Materials For Sodium-Ion Batteries, Yong-Chang Liu, Cheng-Cheng Chen, Ning Zhang, Liu-Bin Wang, Xing-De Xiang, Jun Chen

Journal of Electrochemistry

Sodium-ion batteries (SIBs) have been considered as a potential large-scale energy storage technology owing to the abundance, wide distribution, and low price of sodium resources. However, the larger and heavier sodium ion as compared to lithium ion makes it difficult to identify appropriate electrode materials with the capability for fast and stable sodium-ion insertion/extraction. Furthermore, the optimization of electrolyte, the matching of cathode and anode materials, and the construction of sodium-ion full batteries with high-performance, high-safety, and low-cost are urgently needed in order to make SIBs commercially available. This review summarizes the up-to-date research progresses in key materials (including cathode, …

Advances And Prospects Of Lithium-Sulfur Batteries, Shou-Yi Yuan, Ying Pang, Li-Na Wang, Yong-Gang Wang, Yong-Yao Xia

Journal of Electrochemistry

Lithium-sulfur batteries have recently attracted worldwide attention due to the high specific theoretical energy density of sulfur cathode (2600 Wh⋅kg^-1), low cost and wide availability of sulfur. However, the practical application of lithium-sulfur batteries has been hindered by several challenges, such as the shuttling of polysulfide intermediates, the large volume expansion of sulfur during charge/discharge and the dendrites formation on lithium anode. Foremost among these is the shuttling effect arising from the dissolution of lithium polysulfides intermediate into the electrolyte from the cathode reaction and their diffusion to the anode where they react with metal lithium to form …

Research Progress Of Si-Based Anode Materials For Lithium-Ion Batteries, Ding-Qiong Chen, Yang Yang, Qiu-Li Li, Jin-Bao Zhao

Journal of Electrochemistry

Owing to its high theoretical specific capacity (4200 mAh·g^-1), silicon is a promising candidate to replace graphite as the anode in lithium ion batteries (LIBs). However, low intrinsic electric conductivity and dramatic volume change (~ 300%) during the process of lithiation and delithiation result in electrode pulverization and capacity loss with cycling, accordingly, the application of silicon as an anode in LIBs has been severely hindered. We will discuss the structure of silicon electrode including synthesis of Si-based composites,the selection of binder for silicon and the fabrication of binder-free Si-based electrode, as well as the electrolyte additive to …

Template-Assisted Hydrothermal Synthesis Of Nio@Co3O4 Hollow Spheres With Hierarchical Porous Surfaces For Supercapacitor Applications, Wen Zhou, Xue-Feng Lu, Ming-Mei Wu, Gao-Ren Li

Journal of Electrochemistry

Hollow structures have shown great potentials in a variety of important applications, such as energy conversion and storage. In order to further enhance the performance, the rational design of hollow structures with higher complexity in terms of composition and structure is highly desirable and still remains a great challenge. In this work, an efficient strategy was established for the fabrication of novel NiO@Co₃O₄ hollow spheres (HSs) with hierarchical porous surfaces by silica spheres template-assisted hydrothermal synthesis. The as-fabricated NiO@Co₃O₄ HSs showed high specific surface area of 219.68 m²·g^-1, and significant …

Effects Of Lithium Salts On The Properties Of Hyperbrandched/Comb-Like Composite Polymer Electrolytes, Xian-Lei Hu, Xiao-Xu Liang, Ming-Qiu Zhang, Ruo-Xin Zhang, Li-Ping Zhang, Wen-Hong Ruan

Journal of Electrochemistry

Based on the chemical characteristics of the hydroxyl group of PVA side-chain, the hyperbrandched poly(amine-ester) (HBPAE) was used to hypergraftingly pretreated nano-silica (SiO₂) and polyving akohol (PVA). And different lithium salts were added to fabricate the SiO₂-g-HBPAE/PVA-g-HBPAE hyperbrandched/comb-like composite polymer electrolytes (CPEs). The dispersion of nanoparticles in matrix was observed by SEM. The effects of different lithium salts on the properties of CPEs were studied by DSC, tensile test and dielectric spectra. The results showed that the hypergrafting method improved the interphase compatibility between SiO₂ and matrix. Sulfonic acid type lithium salts accelerated self-plasticizing with …

The Study Of Dynamical Electrochemical Impedance Spectroscopy For Oxygen Reduction Reaction On Pt/C Catalyst, Kun-Ming Shi, Jian-Wei Guo, Jia Wang

Journal of Electrochemistry

With joint techniques of rotating disc electrode(RDE) and electrochemical impedance spectroscopy(EIS), and further establishment on equivalent circuit model, this paper studied oxygen reduction reaction(ORR) on commercial Pt/C catalyst in acid medium. Our results found that the dynamical interface on Pt/C consists of two independent processes: 1) the PtO reduction from Pt surface, 2) the new PtO formation from ORR, thus providing key clues for catalyst stability and activity. This also implied that the dynamical interface facilitates reconstruction for porous electrode, and matches with mass transfer. One important issue is discovered that at high overpotential, the high reaction rate for ORR …

Metal-Organic Hybrid Nanocomposites For Energy Harvesting Applications, Thulitha Madawa Abeywickrama

Masters Theses & Specialist Projects

Various synthetic methods have been developed to produce metal nanostructures including copper and iron nanostructures. Modification of nanoparticle surface to enhance their characteristic properties through surface functionalization with organic ligands ranging from small molecules to polymeric materials including organic semiconducting polymers is a key interest in nanoscience. However, most of the synthetic methods developed in the past depend widely on non-aqueous solvents, toxic reducing agents, and high temperature and high-pressure conditions. Therefore, to produce metal nanostructures and their nanocomposites with a simpler and greener method is indeed necessary and desirable for their nano-scale applications. Hence the objective of this thesis …

Preface-Jes Focus Issue On Electrolysis For Increased Renewable Energy Penetration, B. Pivovar, M. Carmo, K. Ayers, X. Zhang, J. O'Brien

Mechanical & Aerospace Engineering Faculty Publications

(First paragraph) Today represents a particularly exciting time, as our planet’s energy system is undergoing major changes due to dramatically decreasing renewable energy prices and increasing societal concerns over greenhouse gas emissions, criteria pollutants (arsenic, mercury, NOx, particulate matter), and climate change. These factors are pushing society toward deep decarbonization of our energy system, perhaps the most challenging issue facing the planet today. Unfortunately, wind and solar energy, while both promising generation sources, come with intermittency challenges and have limitations in their abilities to impact industrial and transportation sector demands where fossil fuel energy carriers based on chemical bonds have …

Application Of Metal-Organic Frameworks In Dye-Sensitized Solar Cells, Ya-Feng Li, Qing-Qing Sun, Ming-Deng Wei

Journal of Electrochemistry

To assemble dye-sensitized solar cells (DSSCs) with high efficiencies, their photoanodes should have large specific surface area to establish a large adsorption amount of dyes and good light-harvesting ability. From this point of view, it will be an interesting topic to explore the application of metal-organic frameworks (MOFs) in the field of DSSCs due to their huge specific surface area. This paper introduces the application of MOFs in photovoltaic devices briefly, and then summaries our approaches in using MOFs in the study of DSSCs, including the pre-treatment and the post-treatment of photoanode, the preparation of photoanode materials and the light …

Prospects Of D-Π-A Structured Porphyrins And Their Photoelectrochemical Application, Shuang-Shuang Liu, Jian-Feng Lu, Ming-Kui Wang

Journal of Electrochemistry

Porphyrins and their metalloderivatives are a class of compounds exhibiting a wide variety of interesting and highly useful properties, such as chlorophyll. Porphyrins are particularly interesting in photoelectrochemical applications due to their structural similarity to chlorophylls in natural photosynthetic systems, as well as their strong and tunable absorption properties. Recently, various porphyrins have been extensively studied for their applications in solar cells, photocatalytic hydrogen production, optical information storage and others. This review will focus on the unique physical and chemical properties of D-π-A structured porphyrins, and their photovoltaic performances in dye-sensitized solar cells. A brief discussion in the future development …

Activation Effect Of Nano-Carbon Derived From Co2 On Lead Electrode In Sulfuric Aqueous Solution, Yu-Qiao Song, Hua Zhu, Guang-Jin Zhao, Wen-Long Wu, Shou-Bin Zhou, Di-Hua Wang

Journal of Electrochemistry

Serious sulfation of the negative plate is one of the most popular reasons of the early failure of lead-acid battery. Addition of nano-carbon was proved to be effective for recovering the sulfated electrode and the property of the carbon material always plays an important role. In this work, a new kind of nano-carbon material with high electrical conductivity and good adsorption capability for heavy metal cations, which is electrochemically prepared from CO₂ in molten carbonates, was tested as activation additive for the sulfated lead electrode by cyclic voltammetry and SEM measurements. The results showed that the as-prepared carbon can …

WoX/Pedot:Pss Double-Layered Hole-Transport Layers For Efficient And Stable Planar Heterojunction Perovskite Solar Cells, Wen-Yuan Qiao, Qiang Guo, Cong Li, Shuang Ma, Fu-Zhi Wang, Song-Yuan Dai, Zhan-Ao Tan

Journal of Electrochemistry

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a commonly used hole-transport material in the perovskite solar cells (PerSCs) structure of perovskite/fullerene planer heterojunction, but it also has a negative effect on the stability of device because of its acidity which will corrode metal oxide transparent electrodes. In this work, a WO_x hole-transport layer with high work function was inserted into the PEDOT: PSS and FTO to enhance the stability and photovoltaic performance. The inserted WO_x layer not only can avoid direct contact between PEDOT:PSS and FTO, but also can further reduce the contact barrier between the electrode interface. We studied the effect …

A Novel Flexible Dye-Sensitized Solar Cell Based On Pt Networks Counter Electrode, Zi-Jie Xu, Fa-Yin Zhang, Xiao-Dan Hong, Wen-Xi Guo, Xiang-Yang Liu, Chang-Jian Lin

Journal of Electrochemistry

Flexible dye-sensitized solar cells (DSSCs) have received widespread attentions in recent years because of their ease of fabrication, low production cost, relatively high chemical stability and flexibility. We report the fabrication of ZnO DSSCs based on the highly flexible, conducting, catalytic and transparent Pt networks counter electrode, and the performance of this solar cell was characterized by SEM, XRD, polarized fluorescence microscope, motor, I-V test station and electrochemical workstation. Compared to Pt nanofiber arrays (NFs), Pt networks not only show a better conductivity, but also exhibit superior transparency and catalytic activity. Furthermore, Pt networks electrode could be constructed on arbitrary …

Fabrications Of Three Copper Sulfide Counter Electrodes And Their Influences On Photovoltaic Properties In Qdsscs, Xiao-Dan Hong, Zi-Jie Xu, Fa-Yin Zhang, Yu-Peng Li, Mei-Dan Ye, Chang-Jian Lin, Wen-Xi Guo

Journal of Electrochemistry

Quantum dot-sensitized solar cells (QDSSCs) have attracted intensive attention in scientific and industrial fields due to their high molar extinction coefficient, spectral tunability by particle size, ease of fabrication, and low cost. In the past years, semiconductor metal sulfides have attracted extensive attention because of their attractive physical and chemical properties for potential applications in many fields,such as PbS, CuS, CoS and CdS. In particular, copper sulfides have become a promising candidate for counter electrode materials in QDSSCs for their outstanding electrochemical and catalytic properties. In order to explore more stable and efficient copper sulfide counter electrode materials, in this …

Hydrothermal One-Step Synthesis Of Layered Nickel/Cobalt Double Hydroxide With Using Shape-Directing Agent And Homogeneous Precipitating Agent, Li-Wei Zhu, Yun-Hai Yan, Hui Jia, Run-Fen Liang

Journal of Electrochemistry

Nickel/cobalt double hydroxide (Ni/Co-DH) has been prepared by facile hydrothermal one-step synthesis method using hexamethylene tetramine (HMT) as a homogeneous precipitating agent and cetyltrimethylammonium bromide (CTAB) as a shape-directing agent. With the hydrolysis of HMT and the use of CTAB, the Ni/Co-DH could be synthesized without additional alkali source, and in the meantime, the Ni/Co-DH exhibited a controlled mesopore size of 13.4 nm and a large BET surface area of 93.6 m² •g^-1 . The X-ray diffraction (XRD) pattern displays that the Ni/Co-DH existed as a mixture of α-Ni(OH)₂-β-Co(OH)₂. The scanning electron microscope (SEM) …

Special Issue: Photoelectrochemistry And New Types Of Solar Cells, Chang-Jian Lin, Yong-Fang Li

Journal of Electrochemistry

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Cathode Buffer Layer For Improving Photovoltaic Performance Of Planar P-I-N Perovskite Solar Cells, Xiao-Dong Liu, Yong-Fang Li

Journal of Electrochemistry

Organic/inorganic hybrid metal halide perovskite semiconductor materials have drawn great attention for the application in solar cells in recent years because of their combined superior photoelectrical properties of inorganic semiconductors (with high dielectric constant and high charge carriers mobility) and organic semiconductors (with good solution processability and high absorbance). The power conversion efficiency (PCE) of the organometal halide perovskite solar cells (pero-SCs) based on CH₃NH₃PbI₃ has been increased dramatically in a few years from 3.8% to a certified 22.1%, primarily owing to the development of new interfacial materials, careful optimization of morphology, and perovskite crystallization …

Theoretical Study Of Photoelectrochemical Reactions And Ec-Sers On Spr Metallic Electrodes Of Silver And Gold, Yuan-Fei Wu, Ran Pang, Meng Zhang, Jian-Zhang Zhou, Bin Ren, Zhong-Qun Tian, De-Yin Wu

Journal of Electrochemistry

At present photoelectrochemistry has received much concern back to nanostructures of noble metals from semiconductor electrodes. This is due to the surface plasmon resonance (SPR) effect of metallic nanostructures, which can effectively convert the far-field light to the near-field light and concentrate the photonic energy to the local surface area with high energy density. Thus, the different enhancement mechanisms, such as the local optical field enhancement, the formation of light generated hot carriers (hot electron-hole pairs), or the photothermal effect, have been proposed in literatures. On the basis of the SPR enhancement effect, the surface-enhanced Raman spectroscopy (SERS) can be …

Photoelectrochemical Water Splitting Cells: Methods For Improving Performance Of Electrodes And Recent Progress On Photocathodes, Kai-Jian Zhu, Wen-Jun Luo, Zhong-Jie Guan, Xin Wen, Zhi-Gang Zou, Wei Huang

Journal of Electrochemistry

Photoelectrochemical water splitting can convert solar energy into hydrogen which is an ideal way to utilize and store solar energy. A p-n tandem cell is considered as the most promising solar water splitting cell due to its high theory conversion efficiency, low cost and photoelectrode material flexibility. However, solar conversion efficiency of a tandem cell is still low in the experiment because of poor performance in a single photoelectrode. In this review, we have introduced some effective approaches to improve the performances of photoelectrodes by reducing recombination of photogenerated carriers in the bulk or on the surface, and suppressing back …

Preparations And Photoelectrochemical Properties Of Phosphate Modified Rgo-Biobr Nanocomposites, Shuang-Ying Chen, Zhi-Jun Li, Xu-Liang Zhang, Kang Hu, Rui Yan, Li-Qiang Jing

Journal of Electrochemistry

The RGO-BiOBr nanocomposites have been successfully synthesized by a hydrothermal process, and then modified with phosphorous acids. The photoelectrochemical properties of the fabricated RGO-BiOBr nanocomposite films were studied. The results indicate that the photocurrent densities of RGO-BiOBr were much larger compared with those of the bare BiOBr, and interestingly, the photocurrent densities were further improved after phosphate modification. Based on the analyses of the produced hydroxyl radical amounts, the enhanced photocurrent densities could be attributed to the introduction of RGO and to the formed negative fields of modified phosphate groups, which are favorable for electrons to be transferred and for …

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …

Correlation Of Polymer Performance And Hansen Solubility Parameters, Daniel Jobse Mania

Master's Theses

Ready-to-use (RTU) grout is becoming more important to the finish and remodeling construction industry. Market research shows it is a fast-growing product that not only is creating its own space, but is beginning to supplant existing technology.

The original intent of this research was to investigate formulation parameters and how they affect grout performance. It was learned that particle size and oil absorption (OA) value are important filler properties that affect performance as much as adequate packing density and optimal pigment volume concentration (PVC) without going beyond critical PVC (CPVC).

Polymer architecture was also determined to be extremely important, but …

Synthesis, Structural Diversity, And Redox Control Of Cyclometalated Monoruthenium Complexes, Zhong-Liang Gong, Jiang-Yang Shao, Yu-Wu Zhong

Journal of Electrochemistry

Cyclometalated ruthenium complexes have received increasing attractions recently due to their excellent redox and photophysical properties. One structural feature of these complexes is that there is a ruthenium-carbon (Ru-C) σ bond presented in the molecule. Three common methods, namely, the “late metalation”, “early metalation”, and “transmetalation” methods, for the synthesis of cyclometalated ruthenium complexes are discussed and summarized. General strategies for the design of cyclometalating ligand and cyclometalated ruthenium complexes are introduced. By using different ancillary ligands, such as pyridine, imidazole, triazole, and pyrimidine, a great number of ruthenium complexes can be prepared. The presence of the Ru-C bond significantly …