Development of cathode material LiFePO_4 in lithium ion battery

[中文文摘]LiFePO4作为一种新型的锂离子电池正极材料,安全性好,价格低廉,环境友好,循环性能稳定。结合本实验室的研究工作,从合成方法,表征手段,循环性能和电导率等方面综述了近年来LiFePO4的发展概况,并提出了LiFePO4进一步可能的发展趋势。[英文文摘]As a cathode material of lithium ion battery, LiFePO4 possesses some excellent characteristics such as good safety, low cost, environment friendly and satisfactory cycle stability. In this paper, the development of LiFePO4 in recent years is discussed in terms of synthesizing methods, characterization ways, cycling performance and electronic conductivity. The prospect of LiFePO4 in the future is also presented.973项目(2002CB211800); 国家自然科学基金(20373058); 福建省科技项目(2003H044)资助

The Role of Microorganisms in the Geochemical Iron Cycle

铁元素虽然只在地壳含量中位列第4,但却是地球上分布最广的变价金属元素之一,微生物介导的铁循环及其与生源要素碳、氮、氧和硫等耦合的氧化还原反应是微生物地球化学循环的重要驱动力.由于铁循环过程中氧化态三价铁Fe(Ⅲ)在环境p H条件下大多以不溶状态存在,因而由其参与的地球化学循环进程通常较为缓慢.研究表明,微生物在铁元素的地球化学循环过程中起着举足轻重的作用,并在该过程中参与矿物的生成与转化.近年来的最新研究发现,参与地球化学铁循环的微生物之间,微生物与矿物之间,以及矿物介导的微生物之间存在着多样的相互作用,而含铁矿物介导的微生物胞外电子传递机制是其中最受瞩目的研究热点.本文综述了微生物介导的地球..

Cu Doping LiFePO_4 and its Electrochemical Performance

[中文文摘]应用固相反应法合成LiFePO4及掺杂Cu2+的LiFePO4,以XRD、XPS表征样品的结构及Fe存在的价态.发现掺杂少量的Cu2+未能改变LiFePO4材料的结构特征以及Fe2+的化学状态,但是Cu2+的掺杂使得LiFePO4材料的晶胞体积变小.充放电测试结果表明少量Cu2+的掺杂能显著地提高LiFePO4材料的大倍率输出能力, LiCu0.02 Fe0.98 PO4, 其1C放电容量可达130 mAh/g以上,较掺杂前提高了20%左右.[英文文摘]LiFePO4 and LiFePO4 doped with Cu2+ ions were synthesized by solid-state reactions.The structure of LiFePO4 and the Fe valence were analyzed by the XRD(X-ray diffraction) and XPS(X-ray photoelectron spectroscopy) respectively.The Cu doping position in LiFePO4 is discussed.It has found that the volume of LiFePO4 by doping Cu2+ ions is reduced.The minim Cu2+ ions doping does not almost change the binding energy of Fe2p1/2 in LiFePO4.According to the experiment results, we conclude that most of the Cu2+ ions substitute the Fe2 + ions in LiFePO4 when a small amount of Cu2 + ions doping is occurred.973项目(2002CB211800); 福建省化学电源科技创新平台(2006H0090)资助

Effects of soil and water conservation measures on eroded soil development in the Loess Plateau

水土保持工程及植被措施实施,对土壤形成条件、土壤特征及土壤发育产生一定影响,而侵蚀土壤发育程度是评价土壤质量变化及其生态环境效应的重要基础。研究黄土高原水土保持措施对侵蚀土壤理化性质、发育和功能的影响,可为水土保持综合治理,改善黄土高原生态环境提供依据。评述长期定位试验的方法及以空间代替时间的原理,研究了在实施不同水土保持措施后,土壤基本理化性状的变化特征。结果表明:随着措施实施年限的增加,土壤的水分环境和土壤有机碳含量发生了明显改善,对土壤结构和功能产生了影响。证明水土保持措施对侵蚀土壤的发育有一定促进作用

Structure and Performance of LiFePO_4/CaB_6 Composites

[中文文摘]采用固相法合成了纯的LiFePO4,并通过两种不同的方法合成了不同CaB6含量的复合物LiFePO4/CaB6.对这些产物进行了粒度、形貌、电导率、振实密度、X射线衍射和充放电性能的研究.实验结果表明,CaB6的掺入虽然没有明显地提高产物的比容量,但却显著地增加了产物的振实密度和电导率.第二种方法合成的产物性能更好,其电导率提高了5个数量级,振实密度提高了65%.[英文文摘]In order to improve the electric conductivity and tap density of lithium iron phosphate,CaB6 was used as a new additive for the first time.LiFePO4 was synthesized by solid sate reaction and LiFePO4/CaB6 composite with different contents of CaB6 was prepared by two different methods.The samples were characterized by granularity,morphology,electric conductivity,tap density,X-ray diffraction and charge-discharge performance.The results show that although the specific capacity of these materials doped with CaB6 was not improved significantly, the tap density and electronic conductivity of these composites increased. The samp les synthesized by the second method exhibit much better performance, and the electronic conductivity of the materials is enhanced by five orders of magnitude and the tap density by 65%.国家“九七三”计划(批准号:2002CB211804)资助

Review of Research on Regional Land Use Change and Its environmental Impacts

以黄土高原为重点 ,对植被变化及其引起的土地利用变化的环境影响的有关研究进行了比较系统的阐述。对植被研究态势 ,土地利用变化对水文生态过程、土壤环境及生物多样性影响做了简要的述评 ,对该领域的目前存在的问题进行了分析 ,并提出了有关进一步研究的建

梨小食心虫高效性诱剂使用方法

梨小食心虫[Grapholitha molesta(Busck)]简称梨小。在我国东北、华北、华东、西北各桃、梨产区普遍发生;在桃、梨混栽的果园发生尤为严重。该虫为害对象包括桃、苹果、李、杏、海棠、樱桃、杨梅等

利用土壤固化材料修建蓄水设施的施工方法

本发明公开了一种利用土壤固化材料纤维敷网增强技术修建蓄水设施的施工工艺，涉及修建蓄水设施的材料与工艺，属于水利工程技术领域。首先将蓄水设施开挖，并刨毛内表面，形成凹凸面，将含有土壤固化材料、土壤、水和纤维的浆液通过水泥砂浆喷射机喷到水窖内表面，随后采用加压密实棍进行压密实处理；将网格布固定在处理好的水窖内表面，二次进行浆液固化和压密实处理；最终形成“土-固化纤维土-网格布-固化纤维土”结构。此结构具有较高的强度和防渗性能，能够满足水窖对防渗和耐久性的需求；塑性施工工艺施工较为方便，降低了施工成本。本发明对推动水资源缺乏地区尤其是干旱半干旱地区的雨水集蓄利用技术的发展具有重要的实用价值

Cu Doping LiFePO_4 and its Electrochemical Performance

应用固相反应法合成LiFePO4及掺杂Cu2+的LiFePO4,以XRD、XPS表征样品的结构及Fe存在的价态.发现掺杂少量的Cu2+未能改变LiFePO4材料的结构特征以及Fe2+的化学状态,但是Cu2+的掺杂使得LiFePO4材料的晶胞体积变小.充放电测试结果表明少量Cu2+的掺杂能显著地提高LiFePO4材料的大倍率输出能力,LiCu0.02Fe0.98PO4,其1C放电容量可达130 mAh/g以上,较掺杂前提高了20%左右.LiFePO4 and LiFePO4 doped with Cu2+ ions were synthesized by solid-state reactions.The structure of LiFePO4 and the Fe valence were analyzed by the XRD(X-ray diffraction) and XPS(X-ray photoelectron spectroscopy) respectively.The Cu doping position in LiFePO4 is discussed.It has found that the volume of LiFePO4 by doping Cu2+ ions is reduced.The minim Cu2+ ions doping does not almost change the binding energy of Fe2p1/2 in LiFePO4.According to the experiment results,we conclude that most of the Cu2+ ions substitute the Fe2+ ions in LiFePO4 when a small amount of Cu2+ ions doping is occurred.作者联系地址：厦门大学固体表面物理化学国家重点实验室化学化工学院化学系,厦门大学固体表面物理化学国家重点实验室化学化工学院化学系,厦门大学固体表面物理化学国家重点实验室化学化工学院化学系,厦门大学固体表面物理化学国家重点实验室化学化工学院化学系 福建厦门361005,福建厦门361005,福建厦门361005,福建厦门361005Author's Address: State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian,Chin