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锂离子蓄电池正极材料表面包覆研究进展 总被引:6,自引:1,他引:5
综述了目前对锂离子蓄电池正极材料主要是LiCoO2、LiMn2O4和LiNiO2及其掺杂衍生物进行表面包覆改性的方法、所用材料、效果以及机理的最新进展。LiCoO2、LiNiO2和LiNi0.8Co0.1Mn0.1O2的热稳定性较差,LiMn2O4和LiNi0.8Co0.2O2由于与电解液的恶性相互作用等原因高温循环性能很差。在正极材料表面通过各种方法包覆一层阻隔物,可弥补材料的缺点,提高材料的实用性。包覆材料主要包括无机氧化物、无机盐、单质和导电聚合物四大类,其中AlPO4和LiMn2O4包覆可明显提高LiCoO2等的热稳定性,LiCoO2、LiAlO2和SiO2包覆可提高LiMn2O4等高温时的循环稳定性。表面包覆是一种非常简便有效的改善锂离子蓄电池正极材料性能的方法,很具有应用前景。 相似文献
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锂离子蓄电池正极材料LiMn2O4--包覆LiCoO2对LiMn2O4循环性能的影响 总被引:7,自引:0,他引:7
将LiMn2O4置于LiAc和CoAc2的混合溶液中,缓慢蒸干溶液,煅烧后获得了包覆LiCoO2的LiMn2O4材料。通过电化学测试研究了钴的包覆量、煅烧温度、煅烧时间对包覆LiCoO2的LiMn2O4材料循环性能的影响,并比较了包覆Li CoO2前后,LiMn2O4材料分别在常温和高温环境下循环性能的差异。实验结果表明,在LiMn2O4的表面包覆LiCoO2,可以使LiMn2O4在常温和高温环境下获得良好的循环性能。 相似文献
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Al2O3包覆LiMn2O4阴极材料的动力学研究 总被引:1,自引:0,他引:1
在尖晶石LiMn2O4颗粒表面包覆Al2O3,获得结构稳定、循环性能优异的锂离子蓄电池阴极材料。采用X射线衍射研究材料晶体结构,通过恒流充放电、循环伏安和交流阻抗(EIS)来研究锂离子在材料中脱嵌和嵌入的动力学机理。电极材料包覆Al2O3以后,交流阻抗图谱上显示有两个半圆和一条斜线,而未包覆的LiMn2O4只有一个半圆和一条斜线。这表明经过Al2O3包覆后,LiMn2O4活性材料与电解液的直接接触被隔断。相应的等效电路也给出,以评估反应动力学。 相似文献
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采用聚合物热解的方法合成了富锂正极材料Li[Li0.2Co0.13Ni0.13Mn0.54]O2(RLMO),并对其进行硼磷玻璃(BPG)表面包覆。经过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)实验表明,材料颗粒尺寸在100~200 nm范围,其表面明显具有非晶包覆层,且表面包覆不会改变材料的主体结构。在2.0~4.8 V范围内进行恒流充放电测试表明,非晶硼磷玻璃包覆材料(BPG-RLMO)具有更高的首次放电比容量(279.5 m Ah/g,30 m A/g)、高的首次库仑效率(91.3%)和优异的循环稳定性(100次循环后容量保持率为86.4%,30 m A/g)。这些结果表明非晶硼磷玻璃包覆可有效抑制电解液的表面分解和所引起的表面结构破坏,提高了材料的首次库仑效率和循环稳定性,为高性能富锂正极材料的发展提供一种可借鉴途径。 相似文献
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介绍了以β-Ni(OH)2、CoSO4、MnSO4和LiOH·H2O为原料,在β-Ni(OH)2表面同时包覆Co、Mn合成锂离子电池正极材料LiNi09Mn0.03Co0.07O2的方法。XRD测试结果表明:样品为α-NaFeO2结构;SEM和EDS结果表明:Co、Mn均包覆在β-Ni(OH)2表面上,且包覆均匀、致密。合成的材料在电流密度为30mA/g下,第二次循环放电容量为194mAh/g,50次循环后容量仍保持为189mAh/g,材料循环性能稳定。 相似文献
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采用锂离子电池聚乙烯(PE)隔膜为基体,在其两侧均匀涂覆厚度为1~2μm混有纳米氧化铝(Al2O3)粉末及胶凝剂的无机有机浆体,得到一种无机复合陶瓷涂层锂离子电池隔膜。通过对该电池隔膜及由此类隔膜制成的电池进行热烘箱测试结果表明:在150℃高温环境下,无机陶瓷涂层隔膜没有出现较大的热收缩,具有优越的热稳定性,能有效提高锂离子电池的热安全性能。由于无机纳米Al2O2颗粒具有较高的比表面积,使得涂覆后的隔膜对电解液具有良好的润湿性及保液性能。采用陶瓷涂层隔膜组装LiFePO2C体系电池并对电池进行1C充放电循环测试,结果表明涂覆后的隔膜能有效提高锂离子电池的容量保持性能。 相似文献
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Chang J.W. Gorur R.S. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1994,1(6):1039-1046
Results of a study performed to obtain a better understanding of the material characteristics responsible for hydrophobicity recovery leading to a high wet surface resistance in silicone rubbers used for outdoor HV insulation, are reported. The samples were obtained from new and artificially aged HV insulators using HTV silicone rubbers (3 different formulations) as weathershed and RTV silicone rubbers (2 different formulations) as a protective coating. The main experimental facilities employed consist of a salt fog chamber for artificially aging the insulators, and a scanning electron microscope (SEM) for material studies. New results of practical significance that have emerged from this study are: (1) hydrophobicity recovery, predominantly due to diffusion of low molecular weight (LMW) silicone polymer chains, occurs with only a fraction (<20%) of the total LMW polymer content initially available in an unaged material surface, (2) LMW chain regeneration and hence surface hydrophobicity recovery occurs even after the initial supply of LMW polymer is depleted, and (3) hydrophobicity recovery is significantly affected by ambient temperature. The results show the same pattern for different formulations of HTV and RTV rubber materials studied. The X-ray Mapping feature in the SEM provides a visual indication of the diffusion process which is a noteworthy contribution 相似文献
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长效防污闪涂料——室温固化硅氟聚合物的研究 总被引:3,自引:0,他引:3
介绍一种室温固化硅氟聚合物(RTVSIF)长效防污闪涂料,用它喷涂后的瓷绝缘子表面具有优异的润滑性和很强的憎水性,从而可以显著提高绝缘子的耐污性能。通过人工加速光老化试验、涂层电性能试验、绝缘子人工污秽试验、自然污秽试验和挂网试运行,表明RTVSIF是一种理想的防污闪涂料。 相似文献
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研究了具备光催化性能和超亲水性能的TiO_2镀膜材料的自清洁作用机理。分别测试不同加水量、涂膜层数和水解时温度对TiO_2镀膜材料性能的影响,优化了传统的溶胶-凝胶镀膜材料的制备方法。基于TiO_2镀膜材料,分析掺入HPC、Si和钒,并分析掺杂后镀膜材料特性的变化。其结果表明,HPC改性导致TiO_2薄膜颗粒纳米化和表面粗糙度增加,使得镀膜材料的光催化性能得到提高,而掺入钒后,使得TiO_2薄膜保持长久的超亲水性。通过实验分析得出,在户外环境下,覆盖掺钒的TiO_2镀膜玻璃和纯TiO_2玻璃光伏组件相比于普通组件能够提升5.87%和2.78%的输出功率。可见这种基于TiO_2的混合镀膜光伏玻璃技术有望在将来的生产中得到具体应用。 相似文献
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Gorur R.S. Mishra J. Tay R. McAfee R. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1996,3(2):299-306
The role played by two major constituents in a room temperature vulcanized (RTV) silicone rubber coating, namely, the inorganic alumina trihydrate (ATH) filler and the silicone polymer, on the coating's electrical performance was examined. The principal variable in the RTV silicone rubber coatings evaluated was the different weight fraction of the silicone polymer and ATH inorganic filler normally used for improving the tracking and erosion resistance. Other formulation details were essentially the same in the cured rubber. The coatings were spray coated on glazed porcelain rods and subjected to accelerated aging in a salt fog chamber. The changes produced by accelerated aging on the contamination withstand capability, leakage current suppression and erosion resistance were determined and correlated with the ratio of polymer to inorganic filler in the coating. It is shown that critical aspects of electrical performance necessary for satisfactory service operation such as contamination withstand capability before flashover and leakage current suppression are superior for the coating with a relatively high ratio of polymer to inorganic filler in comparison to the coatings with a relatively low ratio of polymer to inorganic filler. While all the coatings showed a high erosion resistance under mild discharge activity, the erosion resistance was found to be superior for the formulations with high inorganic filler under conditions of intensive surface discharge activity 相似文献