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1.
以戊二醛(GA)与3-氨丙基三乙氧基硅烷(KH-550)为原料,通过醛胺缩合反应、高温煅烧以及碱刻蚀,制备了分级多孔纳米碳球(HPCN)。扫描电子显微镜(SEM)测试表明,制备的HPCN为平均粒径85.3 nm的单分散纳米球。将HPCN与单质S混合,通过熔融-扩散法制备HPCN/S正极材料,组装成锂硫(Li-S)电池后进行电化学测试。测试结果表明,HPCN/S具有优良的电化学性能,使用铝箔集流体时,在0.2 C循环100圈后放电比容量为472.1 mA∙h/g;采用碳纸替代铝箔集流体制备的HPCN/S-CP正极,显示出更加优异的循环稳定性与倍率性能,在0.2 C循环100圈后放电比容量为636.1 mA∙h/g,在1.0 C与2.0 C下的倍率比容量分别为702.7 mA∙h/g、249.4 mA∙h/g。 相似文献
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合成了不同Rb掺杂量的钛酸锂(Li4-xRbxTi5O12; x = 0.010, 0.015, 0.020)作为锂离子电池的负极材料。测试结果显示,Rb离子掺杂有效增强了钛酸锂的电子电导率。相同的测试条件下,相比于未掺杂样品和高Rb含量掺杂样品(x = 0.015, 0.020),适量的Rb掺杂钛酸锂(Li3.99Rb0.01Ti5O12; x = 0.010)表现出最优的电化学性能。Li3.99Rb0.01Ti5O12材料表现出161.2 mA∙h/g的初始容量,且在1 C下经过1000次循环后容量保持率可达90.9%。此外,全电池Li3.99Rb0.01Ti5O12 // LiFePO4在0.5 C条件下首次放电容量为144 mA∙h/g,经过150次循环后,容量保持率为78.8%。 相似文献
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直接在铜基底上生长具有不同金属离子的多孔过渡金属氧化物,成为有前途的锂离子电池电极材料的候选。本文提出了一种简便可行的低温水热沉积方法在铜基底上制备前驱物阵列。前驱物经过煅烧处理得到具有多孔特性Co3V2O8纳米片阵列,多孔纳米片阵列用作锂离子电池负极材料显示出了长期循环稳定性和高倍率性能。在1.0 A/g电流密度下,电池经过240次循环后显示出1 010 mA∙h/g的容量;在3.0 A/g的电流密度下,电池循环600次后显示出552 mA∙h/g的可逆容量。 相似文献
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Synthesis of LiNi0.8Co0.2O2 cathode material through sintering in an air environment and electrochemical properties characterization
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制备锂离子电池正极材料LiNi0.8Co0.2O2通常需要在纯氧气气氛下进行烧结.本工作以硫酸镍,硫酸钴和氢氧化钠为原料,采用并流共沉淀法制备了高密度Ni0.8Co0.2(OH)2前驱体,再采用高温固相反应法在空气中烧结制备了锂离子电池LiNi0.8Co0.2O2正极材料.采用X射线衍射(XRD),扫描电镜(SEM),恒流充放电测试(ECT),循环伏安(CV)与比表面积(BET)测试等方法对目标样品进行了表征,详细考察了烧结条件对材料结构,微观形貌及电化学性能的影响.结果表明,锂/(钴+镍)摩尔比为1.13∶1时,在管式炉中和空气气氛下于第一段烧结温度700 ℃保温9 h,于第二段烧结温度750 ℃保温12 h,合成的材料比表面积适中(0.78 m2/g),具有规则的六边形α-NaFeO2层状结构,晶粒分布均匀,电化学性能最优.在0.5 C充放电倍率下和2.7~4.3 V电压范围内,其首次放电比容量达到153.0 mA·h/g,循环20次后放电比容量仍为150.7 mA·h/g,容量保持率达到98.5%,显示了优异的循环稳定性能,可用做高能量密度动力电池正极材料. 相似文献
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Microstructure and energy storage properties of Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2 cathode materials
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WANG Chunlei REN Chong KONG Jizhou ZHOU Fei LI Junxiu YU Chao TANG Weiping 《储能科学与技术》2015,4(4):407-411
以碳酸钠为沉淀剂,乳酸钠为络合剂合成碳酸盐前驱体,950℃烧结制备了Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2(x=0, 0.02, 0.04, 0.06)系列材料,探讨元素含量变化对材料的结构、形貌、充放电性能的影响。研究结果表明:随着x的增大,材料的晶格常数c/a比值增加,层状结构更加完整。当x=0.02时,该材料的充放电性能最优,其首次放电容量为261.0 mA·h/g,0.5C下循环100次后的放电容量仍有189.9 mA·h/g,容量保持率高达98.85%,2C倍率下放电容量最高达到157.6 mA·h/g。进一步增大x值时,由于Co含量的上升,使得更多的Co3+/4+ 2g轨道与O2- 2p轨道发生带隙重叠,从而使得材料的比容量和循环性能下降。 相似文献
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Novel ionic plastic crystal-polymeric ionic liquid all-solid-state electrolytes for lithium ion batteries
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离子塑性晶体作为一类新型的固态电解质材料,近年来受到研究人员的极大关注。本文合成了一种新型离子塑性晶体:N,N-二甲基吡咯双氟磺酰亚胺(P11FSI),并将其与吡咯阳离子离子液体聚合物-聚二甲基二烯丙基铵双氟磺酰亚胺(PILFSI)和锂盐(LiFSI)复合制备了P11FSI-PILFSI-LiFSI全固态电解质。采用差示扫描量热法、热重分析、阻抗测试、线性扫描伏安法及对称锂电池测试等一系列表征技术对全固态电解质的热性能和电化学性能进行了系统研究。所制备的电解质膜具有好的柔韧性和热稳定性,高的离子电导率和电化学稳定性,以及与金属锂良好的界面相容性。将全固态电解质应用于Li/LiFePO4电池中,在50℃、0.2 C充放电倍率时,电池放电比容量在60次循环后仍可达151.1 mA·h/g,容量保持率为96.8%;且在0.5 C、1.0 C倍率下放电比容量仍然高达138.1 mA·h/g和128.1 mA·h/g,展现出高的放电比容量,好的循环性能和倍率性能,有望应用于全固态锂离子电池中。 相似文献
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锂硒电池因其可观的体积比容量(3254 mA·h/cm3),已经引起了国内外研究学者们的广泛关注。本 文在介绍锂硒电池硒/碳正极材料的基础上,指出了锂硒电池目前存在的主要问题,并提出了可能的解决方案,最后对未来锂硒电池的研究方向做出了展望。 相似文献
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硅在自然界中储量丰富,其理论比容量高达4 200 mA∙h/g,已成为高能量密度锂离子电池负极材料的研究热点。但是Si作为负极材料也存在许多不足,最大的问题是电池充放电过程中,硅体积膨胀(高达300%),导致Si基负极材料粉化脱落、电池容量迅速衰减,其循环性能尚难以满足实际需求。通过研究开发硅基负极专用黏结剂材料,可以有效抑制循环过程中硅的体积变化,维持硅负极结构稳定,提升电池循环性能。本文综述了近年来硅基负极黏结剂材料的研究进展,主要从合成高分子聚合物黏结剂、天然高分子聚合物黏结剂、导电高分子聚合物黏结剂三个方面进行详细归纳总结,并介绍了本课题组在硅基负极黏结剂方面的部分研究成果,期望能为将来的硅基负极专用黏结剂的研究和应用提供一些思路。 相似文献
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硅负极具有高比容量的显著优势,其理论比容量(4 200 mA∙h/g)达到传统石墨负极的10倍以上,被认为是锂离子电池最有潜力的负极之一。然而,硅负极存在导电性较差、充放电过程中体积膨胀巨大等诸多问题,导致其循环性能较差,限制了大规模实际应用。本文提供了一种高性能硅负极的制备方法及应用,通过将硅负极分散在多级孔碳中,连同黏结剂聚丙烯腈涂覆在集流体上,再对极片进行热处理实现聚丙烯腈碳包覆,有效提高电极的整体导电性并能为巨大的体积变化提供空间,从而提升硅负极的大倍率性能和循环稳定性。 相似文献
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C. Korepp W. Kern E.A. Lanzer P.R. Raimann J.O. Besenhard M. Yang K.-C. Möller D.-T. Shieh M. Winter 《Journal of power sources》2007
Electrochemical properties and working mechanisms of benzyl isocyanate compounds as polymerizable electrolyte additives for overcharge protection of lithium ion batteries have been studied by cyclic voltammetry, charge–discharge cycling, overcharge tests, accelerating rate calorimetry (ARC) and in situ Fourier transform infrared spectroscopy (FTIRS). The overcharge and FTIRS data clearly reveal that 4-bromobenzyl isocyanate (Br-BIC) can electrochemically polymerize at 5.5 V (versus Li/Li+) to form an overcharge-inhibiting (probably insulating) film on the cathode surface. In addition, is found the Br-BIC does slightly improve the charge/discharge performance of a lithium ion battery. Furthermore, Br-BIC and benzyl isocyanate show beneficial solid electrolyte interphase (SEI) formation behaviour on graphite in propylene carbonate based electrolyte solutions. 相似文献
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Organic compounds with heteroatoms as overcharge protection additives for lithium cells 总被引:1,自引:0,他引:1
Yuu Watanabe Yohei Yamazaki Kazuhiro Yasuda Hideyuki Morimoto Shin-Ichi Tobishima 《Journal of power sources》2006,160(2):1375-1380
Various organic compounds with heteroatoms (N, O, F, Si, P, S) were tested as overcharge protection additives for 4-V class lithium cells. It was found that trimethyl-3,5-xylylsilane exhibited preferable oxidation potential (Eox) as overcharge protection additive, and charge–discharge cycling efficiency (Eff) of lithium anode in electrolyte with arylsilanes was as high as tolyladamantanes, reported previously by us. From room temperature to 60 °C, Eox of trimethyl-3,5-xylylsilane decreased only 0.07 V. Difference in Eox among regioisomers of tolyltrimethylsilanes is smaller than that among tolyladamantanes. 1H NMR and UV spectra suggest the steric repulsion between tolyl group and trimethylsilyl group in o-tolyltrimethylsilane is smaller than that of the related substituents of o-tolyladamantane. 相似文献
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以提高磷酸铁锂体系动力电池的能量密度为目的,在LiFePO4正极材料中加入少量S材料球磨制得LiFePO4/S复合正极材料。使用X射线衍射(XRD)和扫描电子显微镜(SEM)表征了结构和形貌,并分别组装扣式电池和软包电池测试其电化学性能。结果表明,磷酸铁锂纳米颗粒致密均匀附着在硫材料表面,构成具有包覆性结构的复合材料。在不同比例的LiFePO4/S复合材料中,硫的添加量为15%的LiFePO4/S复合正极材料表现出最优异的电化学性能,0.1 C下的初始容量为251.5mA·h/g,循环100周之后容量保持率达94.9%。以该比例的复合材料为正极的0.5A·h软包电池,循环100周后容量保持率为86.7%。LiFePO4作为一种极性载体,对多硫化物有一定的吸附能力,少量硫的加入可以在大幅度提高LiFePO4材料放电容量的同时,维持优异的循环稳定性。LiFePO4/S复合材料可为磷酸铁锂体系动力电池的发展提供新的思路。 相似文献
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锂离子电池内短路是诱发电池热失控的主要原因,适当的安全性添加剂可以阻止电池热失控的发生。本文通过界面聚合法在聚乙烯蜡表面生成适量的导电聚苯胺,制备了一种具有良好导电性能的PTC材料(PANI-PEW),并对PANI-PEW的微观形貌、电导率以及添加至LiFePO4正极中的电化学性能进行了对比分析。测试结果表明,PANI-PEW在常温下的电导率为1.08×10-3 S/m,在90~120℃时,其电阻值急剧增大。在0.5 C和1 C倍率下,PANI-PEW的加入对LiFePO4电池的阻抗和循环性能影响较小,而经过120℃热处理后的含15%(质量分数) PANI-PEW的极片,其电池的阻抗大幅增加且首次放电比容量只有35.3 mA·h/g,在第12次循环后,放电比容量接近于0。以上结果表明,PANI-PEW是一种性能优异的PTC材料且能在120℃时阻止电池热失控的发生。 相似文献
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LiFePO4/C was prepared by solid-state reaction from Li3PO4, Fe3(PO4)2·8H2O, carbon and glucose in a few minutes in a scientific MW (microwave) oven with temperature and power control. The material was characterized by X-ray diffraction, scanning electron microscopy and by TGA analysis to evaluate carbon content. The electrochemical characterization as positive electrode in EC (ethylene carbonate)–DMC (dimethylcarbonate) 1 M LiPF6 was performed by galvanostatic charge–discharge cycles at C/10 to evaluate specific capacity and by sequences of 10 s discharge–charge pulses, at different high C-rates (5–45C) to evaluate pulse-specific power in simulate operative conditions for full-HEV application. The maximum pulse-specific power and, particularly, pulse efficiency values are quite high and make MW synthesis a very promising route for mass production of LiFePO4/C for full-HEV batteries at low energy costs. 相似文献
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Redox shuttle electrolyte additives have been suggested as a possible mean of internal overcharge protection of secondary lithium-ion batteries. TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) is one of these redox shuttles for overcharge protection of 3 V class Li-ion cells. The electrochemical reversibility and the diffusion coefficient of this molecule has been evaluated by mean of cyclic voltammetry. The redox shuttle voltage was found to be 3.5 V versus Li/Li+ and D = cm2 s−1. The electrochemical stability of TEMPO in different overcharging conditions has been evaluated by long-term cycling using Li/Li4Ti5O12 cells. Results show that the TEMPO redox system does not act as an ideal shuttle. When dissolved in the electrolyte at 0.5 M, this additive is able to level off the cell potential at 3.5 V for a long period at low overcharging current (C/200 to C/50). Nevertheless, it appears that the cell capacity fades drastically at the first cycles and with time. This phenomenon is probably related to the stability of the oxidized and reduced form of the TEMPO molecule. 相似文献
17.
Wei WengZhengcheng Zhang Paul C. RedfernLarry A. Curtiss Khalil Amine 《Journal of power sources》2011,196(3):1530-1536
The derivatives of 1,3-benzodioxan (DBBD1) and 1,4-benzodioxan (DBBD2) bearing two tert-butyl groups have been synthesized as new redox shuttle additives for overcharge protection of lithium-ion batteries. Both compounds exhibit a reversible redox wave over 4 V vs Li/Li+ with better solubility in a commercial electrolyte (1.2 M LiPF6 dissolved in ethylene carbonate/ethyl methyl carbonate (EC/EMC 3/7) than the di-tert-butyl-substituted 1,4-dimethoxybenzene (DDB). The electrochemical stability of DBBD1 and DBBD2 was tested under charge/discharge cycles with 100% overcharge at each cycle in MCMB/LiFePO4 and Li4Ti5O12/LiFePO4 cells. DBBD2 shows significantly better performance than DBBD1 for both cell chemistries. The structural difference and reaction energies for decomposition have been studied by density functional calculations. 相似文献
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Nan Ji Yun Hyung-Wook Ha Kyung Hee Jeong Heon-Yong Park Keon Kim 《Journal of power sources》2006,160(2):1361-1368
Olivine structure LiFePO4/C composite powders are synthesized as cathode materials for Li-ion batteries via a conventional solid-state reaction. Improvement in electrochemical performance has been achieved by using poly(vinyl alcohol) as the carbon sources for the as-prepared materials. The influence of the heat treatment on the physical and the electrochemical properties of LiFePO4/C materials is investigated. To examine the effect of added carbon content on the properties of materials, a one-step heat treatment has been employed with control of the PVA content in the precursor. Six samples were prepared with 0, 1, 3, 5, 10 and 30 wt.% PVA added to the raw materials. The particle size of LiFePO4 decreases as the carbon content increases. Materials with medium carbon contents have a small charge-transfer resistance and thus exhibit superior electrochemical performance. Interestingly, for a LiFePO4/C composite with a low PVA content, an unusual plateau at 4.3 V is observed. It is considered that this is due to the Fe3+/Fe4+ redox reaction of Fe3+ compounds that are present as an impurity. For samples with a high PVA amount, a thicker carbon coating provides an obstacle to improve the electrochemical properties. 相似文献