Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy,
2017
Tbilisi State University
Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy, J. Chigvinadze, Juana Acrivos, S. Ashimov, D. Gulamova, G. Donadze
Faculty Publications, Chemistry
When investigating low-frequency (0.1 Hz) oscillations of multiphase high-temperature cuprate superconductors (HTCS) Bi1,7Pb0,3Sr2Ca(n-1)CunOy (n=2-30), a wide attenuation peak (ΔT~100 К) with a maximum at Т≈200 К was detected. This peak was particularly pronounced in field cooling (FC) experiments, i.e. after abrupt cooling of the sample in the external magnetic field at the temperature Т<Тс with subsequent slow warming up to room temperature with invariance of the applied field. The attenuation peak height depended on the preliminaryorientation (before cooling) of the samples θ in the measured permanent magnetic field Н. On the one hand, it is well known that, after the FC procedure and subsequent slow warming up, at the temperatures close to the critical temperature Тс, the attenuation peak associated with “melting” of the Abrikosov frozen vortex structure and its disappearance at Т >Тс is detected in monophase samples. At the same time, in most multiphase bismuth HTCS samples, synthesized using solar energy and superfast quenching of the melt, the attenuation peak with the maximum at Т≈200 К was observed.Depending on the conditions of synthesis, the attenuation peak could …
Special Issue On Supercapacitors,
2017
College of Materials Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, P. R. China;
Strategies To Enhance Energy Density For Supercapacitors,
2017
Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Lanzhou 730000, P. R. China;
Strategies To Enhance Energy Density For Supercapacitors, Jun-Wei Lang, Xu Zhang, Ru-Tao Wang, Xing-Bin Yan
Journal of Electrochemistry
The biggest advantage of supercapacitor lies in not only the excellent pulse and fast charging-discharging performance, but also the characteristics of long cycle life and wide operating temperature window with no pollution. However, the energy density of supercapacitor is low. In this paper, the working principle, the development status, defects and improvement method of supercapacitors are introduced. Based on the research workes of the supercapacitors with high energy density in our group, combined with the literature reports in recent years, the strategies to promote the energy density of supercarpacitors will be focused. The strategies for the enhancement of energy density …
Porous Carbon Materials Produced By Koh Activation For Supercapacitor Electrodes,
2017
CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, & iChEM, University of Science and Technology of China, Hefei 230026, P. R. China;
Porous Carbon Materials Produced By Koh Activation For Supercapacitor Electrodes, Jiang-Lin Ye, Yan-Wu Zhu
Journal of Electrochemistry
Porous carbon materials with high specific surface area and excellent conductivity have wide applications in supercapacitor electrodes. Much effort has been made to synthesize and tailor the microstructures of porous carbon materials via various activation procedures (physical and chemical activations). In particular, the chemical activation using potassium hydroxide (KOH) as an activating reagent is promising because of the well-defined micropore size distribution and ultrahigh specific surface area up to 3000 m2·g-1 of the resulting porous carbons. Based mainly on the previous works taken by the authors and collaborators in the field, we have summarized the activation mechanism …
Recent Advances On Carbon And Transition Metallic Compound Electrodes For High-Performance Supercapacitors,
2017
MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, People’s Republic of China;
Recent Advances On Carbon And Transition Metallic Compound Electrodes For High-Performance Supercapacitors, Dun Lin, Xi-Yue Zhang, Yin-Xiang Zeng, Ming-Hao Yu, Xi-Hong Lu, Ye-Xiang Tong
Journal of Electrochemistry
Supercapacitors (SCs) have stimulated intensive interests for their promising applications in electric vehicles and portable electronics, etc. Electrode material is the most important key component of SCs, which vastly determines the performance of SCs. Carbon and transition metallic compound materials have attracted considerable attention and been widely explored as electrode materials. However, the insufficient capacitance of carbon materials and unsatisfactory conductivity and cyclic stability of transition metallic compounds severely limit their implementation as robust SC electrodes. Herein, we highlight our recent efforts to boost the capacitive performance of carbon and metal oxide/nitride electrodes by rationally structural and componential design. The …
Lithium Ion Hybrid Capacitor With High Energy Density,
2017
Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, PR China;University of Chinese Academy of Sciences, Beijing 100049, PR China;
Lithium Ion Hybrid Capacitor With High Energy Density, Xian-Zhong Sun, Xiong Zhang, Kai Wang, Yan-Wei Ma
Journal of Electrochemistry
Lithium ion hybrid capacitors are electrochemical energy storage devices combining the advantages of both Li-ion battery and electrochemical capacitor. They can be extensively used in many fields. However, the commercialization of lithium ion hybrid capacitor has been encountered several problems, e.g., the device structure design, the screening of materials, the pre-lithiation process, and the interface between electrolyte and electrode, etc. This review summarizes the recent research advances in lithium ion hybrid capacitor with high energy density, including the selection of the active materials in cathode/anode and the separator, the pre-lithiation method using the three-electrode structure, the high- and low-temperature performances, …
Template Induced Fabrication Of Nitrogen Doped Carbon Sheets As Electrode Materials In Supercapacitors,
2017
School of Chemistry and chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
Template Induced Fabrication Of Nitrogen Doped Carbon Sheets As Electrode Materials In Supercapacitors, Tao Huang, Guang-Zhi Tao, Chong-Qing Yang, Deng Lu, Lie Ma, Dong-Qing Wu
Journal of Electrochemistry
Due to the good electrical conductivity, high specific surface area, and excellent chemical/mechanical stability, carbon nanomaterials with two-dimensional morphology have gradually become the hot topic of the research on supercapacitors. Herein, we report for the first time the fabrication of nitrogen doped carbon sheets (NCSs). In our approach, the sheet-like magnisum aluminum (MgAl) layered double hydroxide was used as the hard template, which was mixed with o-phenylene diamine and iron chloride. The following thermal treatment could render the polymerization and carbonization of o-phenylene diamine. The NCSs with ordered hexagonal architectures were formed by final etching process of the thermally treated …
Preparation And Characterization Of Cellulose Acetate-Based Separator For Lithium-Ion Batteries,
2017
Coal Engineering College, Shanxi Datong University, Datong 037003, Shanxi, China;
Preparation And Characterization Of Cellulose Acetate-Based Separator For Lithium-Ion Batteries, Hua-Feng Luo, Yuan-Dong Qiao
Journal of Electrochemistry
To improve the electrolyte wettability and thermal resistance of separators used for lithium-ion battery, a novel cellulose acetate (CA)-based separator is facilely prepared by non-solvent induced phase separation (NIPS) wet-process and investigated in lithium-ion batteries. Systematical investigations including morphological characterization, electrolyte wettability and thermal resistance testing were carried out. The results demonstrated that the CA-based separator exhibited well developed three-dimensional porous structures with porosity up to 65%, which is 1.5 times higher than that of PE separator. The CA separator also showed excellent electrolyte uptake (285%) and thermal stability at 150 oC for 30 min. Compared with the commercial …
Responsive Nanogel Probe For Ratiometric Fluorescent Sensing Of Ph And Strain In Hydrogels,
2017
University of Manchester
Responsive Nanogel Probe For Ratiometric Fluorescent Sensing Of Ph And Strain In Hydrogels, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, Amir H. Milani, Zhengxing Cui, Nam T. Nguyen, Mu Chen, L. Andrew Lyon, Daman J. Adlam, Anthony J. Freemont, Judith A. Hoyland, Brian R. Saunders
Engineering Faculty Articles and Research
In this study a new pH-responsive nanogel probe containing a complementary nonradiative resonance energy transfer (NRET) fluorophore pair is investigated and its ability to act as a versatile probe of network-related changes in three hydrogels demonstrated. Fluorescent sensing using NRET is a powerful method for studying relationships between Angstrom length-scale structure and macroscopic properties of soft matter. Unfortunately, inclusion of NRET fluorophores into such materials requires material-specific chemistry. Here, low concentrations of preformed nanogel probes were included into hydrogel hosts. Ratiometric photoluminescence (PL) data for the gels labeled with the nanogel probes enabled pH-triggered swelling and deswelling to be studied …
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots,
2017
University of Kentucky
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim
Chemistry Faculty Publications
The optical properties of top-down synthesized oxidized graphene quantum dots (ox-GQDs) and nitrogen-incorporating graphene quantum dots (N-GQDs) along a range of hydrothermal treatment temperatures were observed. By controlling the hydrothermal treatment temperature, different chemical states of nitrogen atoms were incorporated into GQDs. Below 150 °C, edge-terminating amines and amides dominated the nitrogen content of N-GQDs. Above 150 °C, nitrogen was primarily present in the forms of pyridinic, pyrrolic and quaternary N. In addition to the absorbance and emission profiles of ox-GQDs and N-GQDs, pH-dependent emission spectra were collected to probe chemical states of nitrogen atoms and investigate the relationship between …
Nano/Submicro-Structured Iron Cobalt Oxides Based Materials For Energy Storage Application,
2017
Western Kentucky University
Nano/Submicro-Structured Iron Cobalt Oxides Based Materials For Energy Storage Application, Hongyan Gao
Masters Theses & Specialist Projects
Supercapacitors, as promising energy storage devices, have been of interest for their long lifespan compared to secondary batteries, high capacitance and excellent reliability compared to conventional dielectric capacitors. Transition metal oxides can be applied as the electrode materials for pseudocapacitors and offer a much higher specific capacitance. Co3O4 is one of the most investigated transition metal oxides for supercapacitor. Besides simple monometallic oxides, bimetallic transition oxides have recently drawn growing attention in electrochemical energy storage. They present many unique properties such as achievable oxidation states, high electrical conductivities because of the coexistence of two different cations in a single crystal …
Feni2se4–Reduced Graphene Oxide Nanocomposite: Enhancing Bifunctional Electrocatalytic Activity For Oxygen Evolution And Reduction Through Synergistic Effects,
2017
Missouri University of Science and Technology
Feni2se4–Reduced Graphene Oxide Nanocomposite: Enhancing Bifunctional Electrocatalytic Activity For Oxygen Evolution And Reduction Through Synergistic Effects, Siddesh Umapathi, Jahangir Masud, Abdurazag T. Swesi, Manashi Nath
Chemistry Faculty Research & Creative Works
Water splitting reaction using earth-abundant and environmentally benign catalysts is critical for renewable energy generation and storage. Herein a hybrid composite, FeNi2Se4 nanoparticles supported on nitrogen doped reduced graphene oxide (FeNi2Se4–NrGO) is reported as an efficient and dependable bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) under alkaline conditions. While FeNi2Se4 nanoparticles themselves show good catalytic activity for water oxidation, the constructed hybrid nanocomposite with NrGO as the supporting matrix show enhanced catalytic activity with a small overpotential of 170 mV @ 10 mA cm …
Toxic Gas Sensing On Nanoporous Carbons,
2017
CUNY Graduate Center
Toxic Gas Sensing On Nanoporous Carbons, Nikolina-Eleni Travlou
Dissertations, Theses, and Capstone Projects
Activated carbons, either synthetic, developed in our laboratory, or commercial, were prepared or further modified, in order to introduce specific heteroatoms such as oxygen, nitrogen and sulfur to their matrices. Chips coated with thin layers of the carbon samples were used for the sensing of gaseous ammonia. They were exposed to continuous cycles of various ammonia concentrations (10-500 ppm), and changes in normalized resistance were analyzed. In all cases linear responses were recorded and the chips reached sensitivities as high as 31%, which are comparable to those of modified graphene-based sensors. The applied specific surface chemical modifications were an effective …
Distinct Ice Patterns On Solid Surfaces With
Various Wettabilities,
2017
Chinese Academy of Sciences
Distinct Ice Patterns On Solid Surfaces With Various Wettabilities, Jie Liu, Chongqin Zhu, Kai Liu, Ying Jiang, Yanlin Song, Joseph S. Francisco, Xiao Cheng Zeng, Jianjun Wang
Xiao Cheng Zeng Publications
No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of …
Optical Studies Of The Solution Phase Reduction And Stabilization Of Indigo Tetrasulfonate In Polyelectrolyte Complexes,
2017
Central Washington University
Optical Studies Of The Solution Phase Reduction And Stabilization Of Indigo Tetrasulfonate In Polyelectrolyte Complexes, Becca Hoene, Dion Rivera
All Faculty Scholarship for the College of the Sciences
Ultraviolet-visible (UV-vis) and fluorescence spectroscopy have been used to characterize the polyelectrolyte complexes (PECs) formed when potassium indigo tetrasulfonate (ITS) interacts with poly diallydimethylammonium chloride (PDADMAC) through columbic attraction in the presence of the reducing agent sodium bisulfite, NaHSO3. The PDADMAC facilitates both the reduction of the ITS and the stabilization of the reduced state of the ITS in an atmospheric oxygen environment. Dilutions of the dye solution show that the PEC is stable to dilutions of at least 1 to 1000. UV–vis studies indicate that the reduced ITS (ITSred) forms what is likely a J-aggregate in the presence of …
Heterojunction Engineering For Next Generation Hybrid Ii-Vi Materials,
2017
CUNY Graduate Center
Heterojunction Engineering For Next Generation Hybrid Ii-Vi Materials, Thor Garcia
Dissertations, Theses, and Capstone Projects
Molecular Beam Epitaxy(MBE) is a versatile thin film growth technique with monolayer control of crystallization. The flexibility and precision afforded by the technique allows for unique control of interfaces and electronic structure of the films grown. This facilitates the realization of novel devices and structures within a research environment normally only achieved though complex industrial processes. In the past, the control of each interface in MBE has been explored to great benefit. In this work, we study the control of these interfaces so as to increase the performance of novel devices material systems. This dissertation focuses on two main areas …
Density Functional Investigation On Cathode/Electrolyte Interface In Solid-State Lithium Batteries,
2017
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
Density Functional Investigation On Cathode/Electrolyte Interface In Solid-State Lithium Batteries, Xuelong Wang, Ruijuan Xiao, Yong Xiang, Hong Li, Liquan Chen
Journal of Electrochemistry
The rapidly expanding application of lithium ion batteries stimulates research interest on energy storage devices with higher energy density, better safety and faster charge/discharge speed. All-solid-state lithium batteries have been considered as promising candidates because of their fewer side reactions and better safety compared with conventional lithium-ion batteries with organic liquid electrolytes. Looking for well-matched electrode/electrolyte interfaces is one of the keys to ensuring good comprehensive performance of solid-state lithium batteries. In this report, with the aid of first-principles simulations, the local structure and lithium ions transportation properties of electrolyte surfaces and cathode/electrolyte interfaces are investigated. The β-Li3PS …
Tetrabutylammonium Hexafluorophosphate As Flame Retardant Additive For Lithium Ion Batteries,
2017
Huai An Institute of Science and Technology Information, Huai'an, 223001;
Tetrabutylammonium Hexafluorophosphate As Flame Retardant Additive For Lithium Ion Batteries, Qing Zhao, Qian Zhang, Jing-Min Fan, Ming-Sen Zheng, Quan-Feng Dong
Journal of Electrochemistry
Safety issues have been attracted more and more attentions due to the wide applications of lithium ion batteries. Introducing flame retardant additives are one of the effective strategies to improve the safety of lithium-ion batteries. In this paper, the tetrabutylammonium hexafluorophosphate (TBAPF6) as a flame retardant additive was added to the electrolyte as a flame retardant additive to enhance the safety of lithium ion batteries. The self-extinguishing time (SET) and ionic conductivities of the electrolytes with different TBAPF6 contents were investigated. It is found that TBAPF6 dramatically reduced the flammability of the electrolyte while slightly decreasing ionic …
Electrochemical Performance Of Sodium Difluoro(Oxalato)Borate As The Additive Of Non-Aqueous Electrolytes For Sodium-Ion Batteries,
2017
College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, 030024, P. R. China;
Electrochemical Performance Of Sodium Difluoro(Oxalato)Borate As The Additive Of Non-Aqueous Electrolytes For Sodium-Ion Batteries, Ding Zhang, Qin Zhu, Ying Wang, Cheng-Long Zhao, Shi-Bin Liu, Shou-Dong Xu
Journal of Electrochemistry
Sodium ion battery has attracted worldwide and intensive attention recently, while the adoption of electrolyte additives has been considered as one effective strategy to promote the cell performance. Within this work sodium difluoro(oxalato)borate (NaDFOB) was prepared and adopted as an additive for the general non-aqueous electrolyte formula of 1 mol·L-1 NaClO4/EC/PC (Vol: Vol=1:1), and the effects of the additive concentration on ionic conductivity and oxidization decomposition voltage were investigated in detail. In addition, the cell performance evaluated by NaNi0.5Mn0.5O2 as the cathode was also studied. It reveals that the addition of NaDFOB into the NaClO4/EC/PC electrolyte resulted in the significantly …
Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis,
2017
Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping He, Qingfeng Ge
Journal of Electrochemistry
Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo2C, W2C, Mo2N and W2N with the adsorption of CO, CO2 and O2. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO2 …
