基于Peukert模型的车用纳米磷酸铁锂电池性能研究

以纳米Li Fe PO4锂离子电池为研究对象,在50--450 A和-18~50℃范围内,对其充放电特性、Peukert模型与温度的关系进行了讨论,利用Ragone曲线对阀控式密封铅酸动力电池、镍氢动力电池及锰酸锂离子电池的能量功率特性进行了对比分析。研究表明,该纳米Li Fe PO4锂离子电池的快速放电能力和能量功率特性都得到很大改善,尤其适合于高温工况;低温性能依然还是纳米Li Fe PO4锂离子电池的弱点,亟待进一步提高。

纳米磷酸铁锂材料的规模化生产与应用研究进展

在我国社会经济的发展过程中,纳米材料是一种不久前刚研发出来的新型材料,有着广阔的市场应用前景。工业和信息化部联合发布的《新材料产业“十二五”发展规划》中提出,要加强纳米技术的研究,提高纳米材料及制品的生产与应用技术水平,确保纳米材料可以广泛应用于新能源领域、节能减排领域以及环境治理领域当中。基于此,本文重点针对纳米磷酸铁锂材料的规模化生产与应用研究进展进行了详细的分析,以供参考。

纳米磷酸铁锂粉尘致肺内小结节样阴影2例报道

回顾性分析2例因职业接触纳米磷酸铁锂粉尘所致肺内小结节样改变病例的临床资料。患者接触纳米磷酸铁锂粉尘2年余,双肺出现弥漫性以q影为主的小结节样致密影,上中肺野分布显著,无胸腔积液,无明显胸痛、呼吸困难等症状,肺通气功能大致正常、小气道功能正常。

石墨烯引导LiFePO_4纳米片的一步溶剂热反应制备及其电化学性能

针对本征低的电子导电率和锂离子迁移速率导致LiFePO_4较差的电化学性能,以石墨烯作为模板,采用一步溶剂热法制备梭形结构的LiFePO_4/石墨烯(LFP/G)复合正极材料;采用XRD和SEM等表征复合正极材料的物相结构和微观形貌,微米级梭型LiFePO_4颗粒是由平均厚度约为55 nm的纳米薄片堆叠而成。电化学性能研究结果表明:在0.1C倍率下,LFP/G复合正极材料的初始可逆比容量可达153.2 mA·h/g,高于相同条件下LiFePO_4的;在10C倍率下充放电时,LFP/G表现出高达85.9m A·h/g的可逆比容量,远高于LiFePO_4的可逆比容量(56.3m A·h/g),展现出明显增强的电化学倍率性能。

A Facile Route for Synthesis of LiFePO_4/C Cathode Material with Nano-sized Primary Particles

A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn（33） space group, which reacts with reduced iron powder to form Li3PO4, Fe3（PO4）2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 ℃. LiFePO4/C prepared at 700 ℃ presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g^-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention.

Liquid-phase preparation and electrochemical property of LiFePO_4/C nanowires

Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.

Ambient synthesis, characterization, and electrochemical activity of LiFePO4 nanomaterials derived from iron phosphate intermediates

LiFePO4 materials have become increasingly popular as a cathode material due to the many benefits they possess including thermal stability, durability, low cost, and long life span. Nevertheless, to broaden the general appeal of this material for practical electrochemical applications, it would be useful to develop a relatively mild, reasonably simple synthesis method of this cathode material. Herein, we describe a generalizable, 2-step methodology of sustainably synthesizing LiFePO4 by incorporating a template-based, ambient, surfactantless, seedless, U-tube protocol in order to generate size and morphologically tailored, crystalline, phase-pure nanowires. The purity, composition, crystallinity, and intrinsic quality of these wires were systematically assessed using transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, selected area electron diffraction （SAED）, energy dispersive analysis of X-rays （EDAX）, and high-resolution synchrotron XRD. From these techniques, we were able to determine that there is an absence of any obvious defects present in our wires, supporting the viability of our synthetic approach. Electrochemical analysis was also employed to assess their electrochemical activity. Although our nanowires do not contain any noticeable impurities, we attribute their less than optimal electrochemical rigor to differences in the chemical bonding between our LiFePO4 nanowires and their bulk-like counterparts. Specifically, we demonstrate for the first time experimentally that the Fe-O3 chemical bond plays an important role in determining the overall conductivity of the material, an assertion which is further supported by recent ＂first-principles＂ calculations. Nonetheless, our ambient, solution-based synthesis technique is capable of generating highly crystalline and phase-pure energy-storage-relevant nanowires that can be tailored so as to fabricate different sized materials of reproducible, reliable morphology.