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Li-ion Batteries (li-ion + battery)

Distribution by Scientific Domains

Polymers and Materials Science	73%
Chemistry	13%

Selected Abstracts

Reversible and High-Capacity Nanostructured Electrode Materials for Li-Ion Batteries

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Min Gyu Kim
Abstract Reversible nanostructured electrode materials are at the center of research relating to rechargeable lithium batteries, which require high power, high capacity, and high safety. The higher capacities and higher rate capabilities for the nanostructured electrode materials than for the bulk counterparts can be attributed to the higher surface area, which reduces the overpotential and allows faster reaction kinetics at the electrode surface. These electrochemical enhancements can lead to versatile potential applications of the batteries and can provide breakthroughs for the currently limited power suppliers of mobile electronics. This Feature Article describes recent research advances on nanostructured cathode and anode materials, such as metals, metal oxides, metal phosphides and LiCoO2, LiNi1,xMxO2 with zero-, one-, two-, and three-dimensional morphologies. [source]

Ultrathin Direct Atomic Layer Deposition on Composite Electrodes for Highly Durable and Safe Li-Ion Batteries

ADVANCED MATERIALS, Issue 19 2010
Yoon Seok Jung
Direct atomic layer deposition (ALD) on composite electrodes leads to ultrathin conformal protective coatings without disrupting inter-particle electronic pathways. Al2O3 -coated natural graphite (NG) electrodes obtained by direct ALD on the as-formed electrode show exceptionally durable capacity retention even at an elevated temperature of 50,°C. In sharp contrast, ALD on powder results in poorer cycle retention than bare NG. [source]

Cover Picture: Nanostructured Electrodes and the Low-Temperature Performance of Li-Ion Batteries (Adv. Mater.

ADVANCED MATERIALS, Issue 1 2005
1/2005)
Abstract The cover image shows a scanning electron micrograph of a commercially available track-etch polycarbonate filter. This porous membrane serves as the host for the template-synthesis of V2O5 nanowires of various diameters. Nanowires that are 70,nm in diameter are shown in the inset. Because V2O5 reversibly intercalates Li-ions, it has potential for use as a cathode material in Li-ion batteries. On p.,125, Sides and Martin report the use of these V2O5 nanowires as tools to investigate the poor low-temperature performance of Li-ion batteries. [source]

Research on Advanced Materials for Li-ion Batteries

ADVANCED MATERIALS, Issue 45 2009
Hong Li
Abstract In order to address power and energy demands of mobile electronics and electric cars, Li-ion technology is urgently being optimized by using alternative materials. This article presents a review of our recent progress dedicated to the anode and cathode materials that have the potential to fulfil the crucial factors of cost, safety, lifetime, durability, power density, and energy density. Nanostructured inorganic compounds have been extensively investigated. Size effects revealed in the storage of lithium through micropores (hard carbon spheres), alloys (Si, SnSb), and conversion reactions (Cr2O3, MnO) are studied. The formation of nano/micro core,shell, dispersed composite, and surface pinning structures can improve their cycling performance. Surface coating on LiCoO2 and LiMn2O4 was found to be an effective way to enhance their thermal and chemical stability and the mechanisms are discussed. Theoretical simulations and experiments on LiFePO4 reveal that alkali metal ions and nitrogen doping into the LiFePO4 lattice are possible approaches to increase its electronic conductivity and does not block transport of lithium ion along the 1D channel. [source]

Li4Ti5O12 Nanoparticles Prepared with Gel-hydrothermal Process as a High Performance Anode Material for Li-ion Batteries

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2010
Zheng Qiu
Abstract Li4Ti5O12 (LTO) nanoparticles were prepared by gel-hydrothermal process and subsequent calcination treatment. Calcination treatment led to structural water removal, decomposition of organics and primary formation of LTO. The formation temperature of spinel LTO nanoparticles was lower than that of bulk materials counterpart prepared by solid-state reaction or by sol-gel processing. Based on the thermal gravimetric analysis (TG) and differential thermal gravimetric (DTG), samples calcined at different temperatures (350, 500 and 700°C) were characterized by X-ray diffraction (XRD), field emitting scanning electron microscopy (FESEM), transmission electron microscopy (TEM), cyclic voltammogram and charge-discharge cycling tests. A phase transition during the calcination process was observed from the XRD patterns. And the sample calcined at 500°C had a distribution of diameters around 20 nm and exhibited large capacity and good high rate capability. The well reversible cyclic voltammetric results of both electrodes indicated enhanced electrochemical kinetics for lithium insertion. It was found that the Li4Ti5O12 anode material prepared through gel-hydrothermal process, when being cycled at 8 C, could preserve 76.6% of the capacity at 0.3 C. Meanwhile, the discharge capacity can reach up to 160.3 mAh·g,1 even after 100 cycles at 1 C, close to the theoretical capacity of 175 mAh·g,1. The gel-hydrothermal method seemed to be a promising method to synthesize LTO nanoparticles with good application in lithium ion batteries and electrochemical cells. [source]

High K Capacitors and OFET Gate Dielectrics from Self-Assembled BaTiO3 and (Ba,Sr)TiO3 Nanocrystals in the Superparaelectric Limit

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010
Limin Huang
Abstract Nanodielectrics is an emerging field with applications in capacitors, gate dielectrics, energy storage, alternatives to Li-ion batteries, and frequency modulation in communications devices. Self-assembly of high k dielectric nanoparticles is a highly attractive means to produce nanostructured films with improved performance,namely dielectric tunability, low leakage, and low loss,as a function of size, composition, and structure. One of the major challenges is conversion of the nanoparticle building block into a reliable thin film device at conditions consistent with integrated device manufacturing or plastic electronics. Here, the development of BaTiO3 and (Ba,Sr)TiO3 superparaelectric uniform nanocrystal (8,12,nm) films prepared at room temperature by evaporative driven assembly with no annealing step is reported. Thin film inorganic and polymer composite capacitors show dielectric constants in the tunable range of 10,30, dependent on composition, and are confirmed to be superparaelectric. Organic thin film transistor (TFT) devices on flexible substrates demonstrate the readiness of nanoparticle-assembled films as gate dielectrics in device fabrication. [source]

Hollow Micro/Nanomaterials with Multilevel Interior Structures

ADVANCED MATERIALS, Issue 36 2009
Yong Zhao
Abstract In this Review, recent achievements in the multilevel interior-structured hollow 0D and 1D micro/nanomaterials are presented and categorized. The 0D multilevel interior-structured micro/nanomaterials are classified into four main interior structural categories that include a macroporous structure, a core-in-hollow-shell structure, a multishell structure, and a multichamber structure. Correspondingly, 1D tubular micro/nanomaterials are of four analogous structures, which are a segmented structure, a wire-in-tube structure, a multiwalled structure, and a multichannel structure. Because of the small sizes and complex interior structures, some special synthetic strategies that are different from routine hollowing methods, are proposed to produce these interior structures. Compared with the same-sized solid or common hollow counterparts, these fantastic multilevel hollow-structured micro/nanomaterials show a good wealth of outstanding properties that enable them broad applications in catalysis, sensors, Li-ion batteries, microreactors, biomedicines, and many others. [source]

Nest-like Silicon Nanospheres for High-Capacity Lithium Storage,

ADVANCED MATERIALS, Issue 22 2007
H. Ma
Nest-like Si nanospheres and their highly reversible lithium storage (3952 mAh g,1 at 100 mA g,1) and excellent high-rate capability (3052 mAh g,1 at 2000 mA g,1) are reported (see figure). This result suggests that the as-prepared nest-like Si nanospheres are promising candidates as the anode materials of rechargeable Li-ion batteries. [source]

A Tin-Based Amorphous Oxide Composite with a Porous, Spherical, Multideck-Cage Morphology as a Highly Reversible Anode Material for Lithium-Ion Batteries,

ADVANCED MATERIALS, Issue 7 2007
Y. Yu
Thin-film anodes for Li-ion batteries prepared by using electrostatic spray deposition are reported. They consist of a tin-based amorphous oxide composite with a porous, spherical, multideck-cage morphology (see figure). The electrochemical properties of the thin-film electrodes are shown to be improved significantly by introducing Li2O and CuO, the ternary Li2O,CuO,SnO2 electrode being demonstrated to exhibit the best performance. [source]

Cover Picture: Nanostructured Electrodes and the Low-Temperature Performance of Li-Ion Batteries (Adv. Mater.

Experimental validation and field performance metrics of a hybrid mobile robot mechanism

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2010
Pinhas Ben-Tzvi
This paper presents the experimental validation and field testing of a novel hybrid mobile robot (HMR) system using a complete physical prototype. The mobile robot system consists of a hybrid mechanism whereby the locomotion platform and manipulator arm are designed as one entity to support both locomotion and manipulation symbiotically and interchangeably. The mechanical design is briefly described along with the related control hardware architecture based on an embedded onboard wireless communication network between the robot's subsystems, including distributed onboard power using Li-ion batteries. The paper focuses on demonstrating through extensive experimental results the qualitative and quantitative field performance improvements of the mechanical design and how it significantly enhances mobile robot functionality in terms of the new operative locomotion and manipulation capabilities that it provides. In terms of traversing challenging obstacles, the robot was able to surmount cylindrical obstacles up to 0.6-m diameter; cross ditches with at least 0.635-m width; climb and descend step obstacles up to 0.7-m height; and climb and descend stairs of different materials (wood, metal, concrete, plastic plaster, etc.), different stair riser and run sizes, and inclinations up to 60 deg. The robot also demonstrated the ability to manipulate objects up to 61 kg before and after flipping over, including pushing capacity of up to 61 kg when lifting objects from underneath. The above-mentioned functions are critical in various challenging applications, such as search and rescue missions, military and police operations, and hazardous site inspections. © 2010 Wiley Periodicals, Inc. [source]

A study on the behavior of a cylindrical type Li-Ion secondary battery under abnormal conditions. Über das Verhalten eines zylindrischen Li-Ionen Akkumulators unter abnormalen Bedingungen

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 5 2010
S. Kim
zylindrische Li-Ionen Akkumulatoren; mechanisches Verhalten; abnormale Bedingungen; Separator Abstract Li-ion (lithium ion) secondary batteries are rechargeable batteries in which lithium ions move between the cathode and the anode. Lithium is not as safe as nickel cadmium (NiCd), and the Li-ion battery can under some conditions increase in temperature and ignite abnormal conditions which includes overcharging, being subjected to an impact, or being hit by a projectile. Before studying causes of Li-ion battery explosions, the term "abnormal condition" was defined. Next, to check the mechanical conditions, an impact test by a free falling object of 9.1 kg weight made of steel was carried out. After the impact test, the damage of the separator around the hollow of the jelly roll in the cell was observed. Following this, the same cell's electrochemical conditions were assessed through a heating test to determine the potential thermal runaway. Finally, to analyze the mechanical damage to the Li-ion batteries during the charging and the impact test, a finite element analysis was performed using LS-DYNA and ABAQUS software. A cylindrical type Li-ion secondary battery was selected for the impact test, heating test, and simulation. The test and simulation results provided insights into the extent to which cylindrical cells can endure abnormal conditions. [source]

Magnetic studies of the carbothermal effect on LiFePO4

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2006
A. Ait-Salah
Abstract The effect of carbon coating on the properties of LiFePO4 particles is studied from magnetic measurements. Magnetization experiments are an excellent tool to detect very low concentrations of iron-based impurities (<1 ppm) which are poisoning the phospho-olivine used as positive electrode material in rechargeable Li-ion batteries. The results indicate that addition of 5% carbon withdraws traces of the Fe(III) phase such as Fe2P and/or Fe2O3. This carbothermal effect appears to be beneficial for long-term application of LiFePO4 materials in Li-ion batteries. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A study on the behavior of a cylindrical type Li-Ion secondary battery under abnormal conditions. Über das Verhalten eines zylindrischen Li-Ionen Akkumulators unter abnormalen Bedingungen

Pyrolysis of a Three-Dimensional MnII/MnIII Network To Give a Multifunctional Porous Manganese Oxide Material

CHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2010
Sanjit Nayak Dr.
Pores for thought! Thermolysis of a 3D coordination network of MnII/MnIII produces a novel spongelike morphology of manganese oxide by a degassing mechanism (see picture). This porous material shows high capacitance when used as an anode in a Li-ion battery and efficient catalytic activity for cyclohexene oxidation. [source]