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镍氢电池的循环性能与活性物质微结构的研究 总被引:1,自引:0,他引:1
与循环试验大致同步, 用静态(初态和终态)或准动态(增加若干个中间态)的模式对MH/H电池循环性能、电极(包括负极和正极)材料的微结构进行了X射线衍射(XRD)研究, 发现循环性能衰减与正极材料β-Ni(OH)2的点阵参数、平均晶粒尺度、微应变和总的层错几率均随循环周期增加而减小以及负极材料中腐蚀产物A(OH)3和B相出现和增加有一定的对应关系, 发现MH/Ni 电池循环性能的衰减是正极材料和负极材料的结构和微结构随着循环次数的增加发生明显变化, 恶化了正负极材料的电化学性能, 同时消耗和恶化了电解液的综合结果. 为了提高电池的循环性能, 采用不同正极材料的添加剂. 结果表明, CaF2和Lu2O3有明显的效果, 其中CaF2效果最好, 并有广泛的实用性. 相似文献
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ZHU Chuan-Zheng YANG Bao-Lin ZHAO Hong GU Wen-Xiu AI Shi-YunDepartment of Chemistry East China Normal University Shanghai China 《中国化学》1997,15(1):68-75
The dissociation constant of each step for TB-chlorosulphophenol has been determined by potentiometric method, and the thermodynamic constants, △G°, △H° and △S°, of the dissociation process have been calculated. The protonation constants were measured by the spectrophotometric method. The pH values of various forms of anions of the chromogenic reagent at their concentrations were also calculated. 相似文献
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利用XRD系统地研究了石墨/Li(Ni1/3Co1/3Mn1/3)O2 18650型锂离子电池充放电过程中正负极活性材料的晶体结构和微结构的变化.已观测到,由于Li原子的脱嵌,使得LiMO2点阵参数a缩小,c增大,微应变增大,衍射强度比I104/I101和I012/I101降低;此外,由于Li原子的嵌入,2H-石墨的点阵参数a和c,以及微应变ε和堆垛无序度P都增加.同时,讨论了活性材料Li(Ni1/3Co1/3Mn1/3)O2和石墨在电池充放电过程中的嵌脱锂的物理机理.在充电时,正极Li(Ni1/3Co1/3Mn1/3)O2中处于(000)位的Li原子优先脱离晶体点阵,继后才是位于(2/3 1/3 1/3)和(1/3 2/3 2/3)位的Li原子离开点阵.锂嵌入石墨,优先进入碳原子六方网格面间的间隙位置,当负极的堆垛无序度达到一定值后,3R相逐渐析出.当电池满充或过充时,在六方石墨中形成LiC12和LiC6相.放电时,与上述过程相反,但并非是完全可逆的.
关键词:
锂离子电池
微结构
X射线衍射
嵌脱锂物理机理 相似文献
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Li Sun Yan-Feng Chen Lei He Chuan-Zheng Ge Tao Yu Ming-Sheng Zhang Nai-Ben Ming De-Sheng Ding Yin-Chuan Chang 《Zeitschrift für Physik B Condensed Matter》1997,102(4):479-482
(001) preferentially oriented PbTiO3 thin films have been grown on (110) NdGaO3 substrates by metalorganic chemical vapor deposition (MOCVD) under reduced pressure at 650°C. Atomic force microscopy (AFM) surface morphology of the as-deposited film showed the evidence of layer-by-layer growth in the MOCVD process. By using a grazing-angle scattering technique, a highly resolved Raman spectrum of the epitaxial PbTiO3thin film on perovskite substrate was first time recorded. Other microstructure of the film, such as the element composition, the c-domain percentage and the epitaxial nature, were investigated by Rutherford backscattering spectrometry (RBS), x-ray θ ? 2θ diffraction patterns and x-ray φ scans, respectively. All measurements indicate that NdGaO3single crystal, which used to be a substrate for the growth of high-Tc superconducting thin films, is also suitable for the growth of high quality PbTiO3 thin film. This indicates the promising use of the NdGaO3 for the integration of ferroelectric thin films and superconducting electrodes. 相似文献
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新型含嘧啶氨基吡唑类化合物的合成及生物活性 总被引:4,自引:0,他引:4
合成了一系列新型含有嘧啶氨基的吡唑类化合物,化合物的结构经1HNMR及元素分析确证.生物活性测试表明,一些化合物对小麦赤霉、番茄早疫、芦笋茎枯、苹果轮纹以及花生褐斑等病害显示出一定的抑制活性,一些化合物具有一定的除草活性,还有的化合物对黄瓜子叶生根有一定的促进作用.实验表明这类化合物结构的变化对活性有重要影响. 相似文献
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