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1.
Transition metal oxides(TMO) bring a novel direction for the development of energy store materials due to their excellent stability. They not only have high capacity and good cycle performance, but also are cheap and easily available. Zinc oxide(Zn O) as an important part of TMO have gradually attracted attention in the research of electrochemistry. Zn O, as a metal semiconductor with the advantages of wide band gap, possesses high ion migration rate, good chemical stability, simple preparation ...  相似文献   

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The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices.  相似文献   

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Nanostructured materials have received tremendous interest due to their unique mechanical/electrical properties and overall behavior contributed by the complex synergy of bulk and interfacial properties for efficient and effective energy conversion and storage. The booming development of nanotechnology affords emerging but effective tools in designing advanced energy material. We reviewed the significant progress and dominated nanostructured energy materials in electrochemical energy conversion and storage devices, including lithium ion batteries, lithium–sulfur batteries, lithium–oxygen batteries, lithium metal batteries, and supercapacitors. The use of nanostructured electrocatalyst for effective electrocatalysis in oxygen reduction and oxygen evolution reactions for fuel cells and metal–air batteries was also included. The challenges in the undesirable side reactions between electrolytes and electrode due to high electrode/electrolyte contact area, low volumetric energy density of electrode owing to low tap density,and uniform production of complex energy materials in working devices should be overcome to fully demonstrate the advanced energy nanostructures for electrochemical energy conversion and storage. The energy chemistry at the interfaces of nanostructured electrode/electrolyte is highly expected to guide the rational design and full demonstration of energy materials in a working device.  相似文献   

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SbPO4, a phosphate with a layered structure, was tested as an electrode material for lithium cells spanning the 3.0-0.0 V range. Two main electrochemical processes were detected as extensive plateaus at ca. 1.6 and 0.7 V in galvanostatic measurements. The first process was found to be irreversible, thus excluding a potential intercalation-like mechanism for the reaction and being better interpreted as a decomposition reaction leading to the formation of elemental Sb. This precludes the use of this compound as a cathodic material for lithium cells. By contrast, the process at 0.7 V is reversible and can be ascribed to the formation of lithium-antimony alloys. The best electrochemical response was obtained by cycling the cell at a C/20 discharge rate over the voltage range 1.25-0.25 V. Under these conditions, the cell delivers an average capacity of 165 Ah/kg—a value greater than those reported for other phosphates—upon successive cycling.  相似文献   

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We present the progress on the physical chemistry of the olivine compounds since the pioneering work of Prof. John Goodenough. This progress has allowed LiFePO4 to become the active cathode element of a new generation of Li-ion batteries that makes a breakthrough in the technology of the energy storage and electric transportation. This achievement is the fruit of about a decade of intensive research in the electrochemical community during which chemists, electrochemists, and physicists added there efforts to understand the properties of the material, to overcome the obstacles that were met on the way, and finally to reach the state of the art that allows its commercial use for worldwide applications in the industry today. These obstacles involved carbon coating, purification, control of the surface, the progressive decrease of the size of the particles down to nanoscale, and comprehensive investigation of surface effects. Nevertheless, heterogeneity in the quality of the product available on the market is damaging and may even be an obstacle to the development of new demanding technologies such as electric transportation. Emphasis is placed on the quality control that is needed to guarantee the reliability and the optimum electrochemical performance of this material as the active cathode element of Li-ion batteries. The route to increase the performance of Li-ion batteries with the other members of the family is also discussed. Since Prof. John Goodenough not only initiated the work but also played a major role in the research and development on these materials through the years, the present review is dedicated to him.  相似文献   

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The structure and anodic performance of boron-doped and undoped mesocarbon microbeads (MCMBs) have been comparatively studied and the results obtained by XPS, XRD, SEM, Raman spectroscopy and electrochemical measurements are discussed. It is found that boron doping introduces a depressed d 002 spacing and the larger amount of "unorganized carbon", which induces vacancy formation in the graphite planes and leads to a quite different morphology from that of the undoped material. Electrochemical charge/discharge cycle tests indicated that after boron doping the lithium intercalation was carried through at a somewhat higher potential, being attended by greater irreversible capacity loss. Electronic Publication  相似文献   

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The activities in progress in our laboratory for the development of batteries and fuel cells for portable electronics and hybrid car applications are reviewed and discussed. In the case of lithium batteries, the research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to disordered carbon anodes and improved, solvent-free, as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes, in combination with suitable electrode couples, allows the development of new types of safe, reliable, and low-cost lithium ion batteries which appear to be very promising power sources for hybrid vehicles. Some of the technologies proven to be successful in the lithium battery area are readapted for use in fuel cells. In particular, this approach has been followed for the preparation of low-cost and stable protonic membranes to be proposed as an alternative to the expensive, perfluorosulfonic membranes presently used in polymer electrolyte membrane fuel cells (PEMFCs).  相似文献   

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Additive manufacturing and 3D printing in particular have the potential to revolutionize existing fabrication processes, where objects with complex structures and shapes can be built with multifunctional material systems. For electrochemical energy storage devices such as batteries and supercapacitors, 3D printing methods allows alternative form factors to be conceived based on the end use application need in mind at the design stage. Additively manufactured energy storage devices require active materials and composites that are printable, and this is influenced by performance requirements and the basic electrochemistry. The interplay between electrochemical response, stability, material type, object complexity and end use application are key to realising 3D printing for electrochemical energy storage. Here, we summarise recent advances and highlight the important role of methods, designs and material selection for energy storage devices made by 3D printing, which is general to the majority of methods in use currently.  相似文献   

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Nano-sized nickel ferrite (NiFe2O4) was prepared by hydrothermal method at low temperature. The crystalline phase, morphology and specific surface area (BET) of the resultant samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and nitrogen physical adsorption, respectively. The particle sizes of the resulting NiFe2O4 samples were in the range of 5–15 nm. The electrochemical performance of NiFe2O4 nanoparticles as the anodic material in lithium ion batteries was tested. It was found that the first discharge capacity of the anode made from NiFe2O4 nanoparticles could reach a very high value of 1314 mAh g−1, while the discharge capacity decreased to 790.8 mAh g−1 and 709.0 mAh g−1 at a current density of 0.2 mA cm−2 after 2 and 3 cycles, respectively. The BET surface area is up to 111.4 m2 g−1. The reaction mechanism between lithium and nickel ferrite was also discussed based on the results of cycle voltammetry (CV) experiments.  相似文献   

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Of the many candidate fuels for low-temperature fuel cells, one of the most promising is formic acid. Although it has been investigated as such for nearly 50 years, rapid advances in recent times have begun to release the potential for formic acid fuel cells as high-performance, portable fuel cells with some products about to reach the market. In this review, we briefly summarise the recent advances in formic acid fuel cells.  相似文献   

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In the scope of developing new electrochemical concepts to build batteries with high energy density,chloride ion batteries(CIBs) have emerged as a candidate for the next generation of novel electrochemical energy storage technologies, which show the potential in matching or even surpassing the current lithium metal batteries in terms of energy density, dendrite-free safety, and elimination of the dependence on the strained lithium and cobalt resources. However, the development of CIBs is still a...  相似文献   

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The review summarizes the development of lithium ion batteries beginning with the research of the 1970–1980s which lead to modern intercalation type batteries. Following the history of lithium ion batteries, material developments are outlined with a look at cathode materials, electrolyte solutions and anode materials. Finally, with lithium sulfur and lithium oxygen batteries two post intercalation type lithium batteries are discussed. The focus of the material discussions lies on basic understanding, problems and opportunities related to the materials.  相似文献   

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Hierarchically ordered porous nickel oxide array film was prepared by electrodeposition through monolayer polystyrene spheres template. The as-prepared film had a highly porous structure of interconnected macrobowls array possessing nanopores. As anode material for lithium ion batteries, the porous array NiO film exhibited weaker polarization, higher coulombic efficiency and better cycling performance in comparison with the dense NiO film. After 50 cycles, the discharge capacity of porous array NiO film was 518 mAh g? 1 at 1 C rate, higher than that of the dense NiO film (287 mAh g? 1). The enhancement of the electrochemical properties was due to the unique hierarchical porous architecture, which provided fast ion/electron transfer and alleviated the structure degradation during the cycling process.  相似文献   

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The sodium lithium titanate with composition Na2Li2Ti6O14 has been synthesized by a sol–gel method. Thermogravimetric analysis and differential thermal analysis (TG–DTA) of the thermal decomposition process of the precursor and X-ray diffraction (XRD) data indicate the crystallization of sodium lithium titanate has occurred at about 600 °C. Electrochemical lithium insertion into Na2Li2Ti6O14 for lithium ion battery has been investigated for the first time. These results indicate the discharge and charge potential plateaus are about 1.3 V. The initial discharge capacity is much higher than the charge capacity and irreversible capacity exists in the voltage window 1–3 V. Subsequently, the discharge capacity decreases slowly, but the charge capacity increases slightly in the following cycles. After a few cycles, the specific capacity remains almost constant values and the sample exhibits the excellent retention of capacity on cycling.  相似文献   

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Platelike CoO/carbon nanofiber (CNF) composite materials with porous structures are synthesized from the thermal decomposition and recrystallization of β-Co(OH)2/CNF precursor without the need for a template or structure-directing agent. As negative electrode materials for lithium-ion batteries, the platelike CoO/CNF composite delivers a high reversible capacity of 700 mAh g−1 for a life extending over hundreds of cycles at a constant current density of 200 mA g−1. More importantly, the composite electrode shows significantly improved rate capability and electrochemical reversibility. Even at a current of 2 C, the platelike CoO/CNF composite maintain a capacity of 580 mAh g−1 after 50 discharge/charge cycles. The improved cycling stability and rate capability of the CoO/CNF composite electrodes may be attributed to synergistic effect of the porous structural stability and improved conductivity through CNF connection.  相似文献   

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Journal of Solid State Electrochemistry - In this research, we conducted a comprehensive interrogation of a direct fucose fuel cell to maximise the electric power and demonstrated the potential for...  相似文献   

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The Si/SiO nanocomposite was synthesized by a sol–gel method in combination with a following heat-treatment process. It was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV) and capacity measurement as anode material for lithium ion battery. Si nanoparticles were coated with SiO and a core-shell structured nanocomposite was formed. The core-shell Si/SiO nanocomposite displays better reversibility of lithium insertion/extraction and higher coulomb efficiency than virginal Si nanoparticles. The SiO shell envelops the Si nanoparticles to suppress the aggregation of the nanoparticles during cycling. As a result, the core-shell Si/SiO nanocomposite exhibits better capacity retention than virginal Si nanoparticles, indicating that this is a promising approach to improve the electrochemical performance of nano anode materials for lithium ion battery.  相似文献   

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