文章编号:1004-0609(2014)03-0779-08
H2SO4表面修饰天然石墨的电化学性能及嵌脱锂动力学
朱华丽1, 2,鲁盼盼2,陈召勇2,李 劼1,陈 奋2,杜炳林2,赖延清1
(1. 中南大学 冶金与环境学院,长沙 410083;
2. 长沙理工大学 物理与电子科学学院,长沙 410004)
摘 要:以硫酸为表面修饰剂,采用浸渍法对天然石墨进行表面修饰改性。傅里叶变换红外光谱仪(FTIR)分析结果表明,硫酸表面修饰的天然石墨表面—OH和C=C消失,—COO-数量增多。电化学性能测试结果表明,经硫酸表面修饰的天然石墨的循环性能和倍率性能均得到提高。经3 mol/L H2SO4处理12 h的天然石墨(NGS3)在0.5C下20次循环后脱锂容量为320.5 mA·h/g;而未经表面修饰的天然石墨(NG)在相同条件下的脱锂容量仅为299.9 mA·h/g。采用交流阻抗谱对石墨进行嵌脱锂动力学研究,结果显示,经硫酸表面修饰的天然石墨膜电阻(RSEI)和电荷转移电阻(Rct)均减小,膜电容(CSEI)和双电层电容(CCPE)增加,多次循环后RSEI保持稳定,NG的活化能(Ea)为87.7 kJ/mol,NGS3的Ea为77.2 kJ/mol,表明 H2SO4修饰有利于锂离子去溶剂化能力的提高,并有利于形成稳定的固体电解质界面(Solid electrolyte interface,SEI)。
关键词:天然石墨;表面修饰;负极;固体电解质界面;交流阻抗;活化能
中图分类号:TQ035 文献标志码:A
Electrochemical performance and kinetics on lithium ion insertion/deinsertion of sulfuric acid surface-modified natural graphite
ZHU Hua-li1, 2, LU Pan-pan2, CHEN Zhao-yong2, LI Jie1, CHEN Fen2, DU Bing-lin2, LAI Yan-qing1
(1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410004, China)
Abstract: The natural graphite was modified by impregnation method with sulfuric acid as surface modification agent. FTIR results show that —OH and C=C bonds on the surface of natural graphite disappear while the number of —COO- increases after sulfuric acid surface-modification. The electrochemical performance reveals that the cycle performance and ratio performance are improved. The lithium-deinsertion capacities of natural graphite impregnated by 3 mol/L H2SO4 for 12 h (NGS3) and unmodified natural graphite (NG) are respectively 320.5 and 299.9 mA·h/g after 20 cycles at 0.5C. AC impedance was used to investigate kinetics on lithium ion insertion/ deinsertion. It is found that the membrane resistance (RSEI) and charge transfer resistance (Rct) decrease, while the membrane capacitance (CSEI) and extracted capacitance (CCPE) increase. Moreover, RSEI keeps constant after several cycles. The activation energies of NG and NGS3 are 87.7 and 77.2 kJ/mol, respectively, which indicates that sulfuric acid treatment is beneficial to the improvement of the desolvation of lithium ion from solvent molecules and the formation of a stable solid electrolyte interface (SEI).
Key word: natural graphite; surface-modification; anode; solid electrolyte interface; alternating impedance; activation energy
天然石墨具有资源丰富、价格低廉等优点,是理想的锂离子电池负极材料。然而,天然石墨形成过程中存在的部分晶格缺陷和嵌锂过程中的溶剂分子共嵌导致其循环过程中发生石墨片层剥离现象,循环性能严重下降[1]。另外,球形石墨同心圆片层堆积结构[2]决定了其大倍率容量不理想。因此,天然石墨须经过改性处理才可满足锂离子电池负极材料的要求。
表面修饰处理一方面可以消除石墨表面的缺陷[3],减少石墨表面的活性点,从而减少锂离子的消耗;另一方面可引入一些纳米级微孔或通道[4],增加储锂位,同时会引入酸性—COO-基团,形成致密的固体电解质界面(SEI)钝化膜[5],从而阻止溶剂的共嵌和分解[6],降低不可逆容量,提高循环寿命,进而改善石墨负极材料的电化学性能[7]。目前,天然石墨的表面修饰方法分为气相法和液相法。气相法表面修饰是由PELED等[8]首次提出的,可选择的气相修饰剂有空气、氧气和CO2等[9-10],采用气相法主要研究了烧失量、煅烧温度和煅烧时间对电化学性能、表面官能团及SEI膜形成的影响。液相法采用的修饰剂有HNO3、H2O2、CeSO4、(NH4)2S2O8和H2SO4等,文献[11-15]主要研究了修饰剂对表面官能团、孔结构及电化学性能的影响。
本文作者采用H2SO4对天然石墨进行表面修饰,优化了反应浓度和反应温度等改性条件。采用交流阻抗谱研究嵌脱锂过程中常相角元件(CPE)[16]包含的双电层电容(CCPE)[17]和膜电容(CSEI)[18]的动力学变化、改性前后的活化能(Ea)变化及其H2SO4表面修饰对天然石墨电化学性能的影响。
1 实验
1.1 样品制备
取25 g球形天然石墨置于带有冷凝回流装置的三口烧瓶中,分别加入100 mL 1、2和3 mol/L的H2SO4溶液,在不同的温度(0、60和100 ℃)下水浴12 h后过滤,所得产物经去离子水反复洗涤至滤液为中性,过滤后产物在100 ℃真空干燥12 h,得到样品,H2SO4表面修饰天然石墨的反应条件见表1。
1.2 材料的表征
利用Nicolet Magna公司生产的AVATAR-360型号傅里叶变换红外光谱仪(FTIR)表征样品表面的化学组分,扫描范围为4000~600 cm-1,分辨率为4 cm-1。
1.3 电池的组装及电化学性能测试
表1 H2SO4表面修饰天然石墨的反应条件
Table1 Reaction conditions of natural graphite surface- modification with H2SO4
按质量比94:2.5:3.5称取天然石墨样品、导电剂(乙炔黑)和粘结剂(PVDF),加入适量的N-甲基吡咯烷酮(NMP)充分混合制成浆料,磁力搅拌2 h,涂覆在厚度为10 μm的铜箔上,于120 ℃真空干燥4 h后冲压成直径为10 mm的圆片作为工作电极,电极面积为0.785 cm2,以金属锂片为对电极,1 mol/L LiPF6/(EC+DMC+EMC) (质量比为1:1:1)为电解液,Celgard 2400为隔膜,在高纯Ar保护的手套箱(米开罗那中国有限公司MIKROUNA Super(1220/750)型)中组装成CR2025型扣式电池。
利用CT2001A型蓝电电池测试仪对电池进行充放电测试。测试电压范围为0~2 V,充放电倍率分别为0.1C、0.2C和0.5C,测试温度为25 ℃。
采用上海辰华公司生产的CHI660B型电化学工作站进行交流阻抗测试。交流阻抗的测试条件如下:扫描的频率范围0.01~100000 Hz,振幅为0.005 V。为了计算活化能,将模拟电池置于高低温实验箱(上海鲁轩GDW/LX-100)中,分别在0、15、25和35 ℃下进行交流阻抗测试。
2 结果与讨论
2.1 FTIR分析
图1所示为经H2SO4表面修饰前 (NG)后(NGS3) 天然石墨的红外光谱。3516和1643 cm-1处的吸收峰分别对应NG表面的羟基(—OH)[19]和炭炭双键(C=C)峰[20],1697和1732 cm-1处吸收峰分别对应NG和NGS3表面的羧基(—COO-)峰[19, 21]。由图1可知, NGS3在3500和1640 cm-1附近的峰消失,—COO-峰增强,这说明H2SO4表面修饰使—COO-基团的数量增加[22]。
2.2 电化学性能
图1 经H2SO4表面修饰前(NG)后(NGS3)天然石墨的傅里叶转换红外光谱
Fig. 1 FTIR spectra of natural graphite samples before (NG) and after (NGS3) H2SO4 surface-modification
经H2SO4表面修饰前后天然石墨的首次嵌脱锂性能见表2。由表2可知,H2SO4表面修饰提高了天然石墨的首次可逆容量,首次可逆容量从345.6 mA·h/g增加到365.0 mA·h/g,不可逆容量和首次效率没有明显的变化。
图2所示为天然石墨和经H2SO4表面修饰的天然石墨在不同倍率下的循环寿命曲线。可见,经H2SO4表面修饰天然石墨的循环性能随H2SO4浓度的增加和反应温度的降低而提高。经H2SO4表面修饰得到的天然石墨样品NGS1、NGS3和NGS3-1,在0.5C倍率下循环20次后的脱锂比容量分别为313.1、320.5和316.8 mA·h/g,容量保持率分别为90.4%、87.8%和88.6%。而未经表面修饰的天然石墨NG在0.5C倍率下循环20次后的脱锂比容量仅为299.9 mA·h/g,容量保持率为86.8%。且经H2SO4表面修饰天然石墨的倍率容量也得到提高,NGS3在0.2C和0.5C下的脱锂比容量分别为339.5和333.8 mA·h/g,对应的容量保持率分别为93.0%和91.5%,而NG在相同条件下的脱锂比容量分别为311.9和294.6 mA·h/g,对应的容量保持率分别为90.2%和85.2%。
H2SO4表面修饰显著提高了天然石墨的电化学性能,可能是由于H2SO4表面修饰后生成大量的RO—COO-[23],RO—COO-与Li+反应生成RO—COOLi[24-25],其为SEI膜的重要成分,能够促进SEI膜的快速形成,从而改善天然石墨的循环性能和倍率性能。
2.3 交流阻抗分析
表2 H2SO4表面修饰前后天然石墨的首次嵌脱锂性能(0.1C)
Table 2 First insertion/deinsertion performance of natural graphite before and after H2SO4 surface-modification (0.1C)
图2 不同条件下表面修饰后天然石墨样品的循环和倍率性能曲线
Fig. 2 Cycle performance and rate capacity of natural graphite surface-modified under different conditions
图3 表面修饰前(NG)后(NGS3)天然石墨样品在不同电压下(0.7,0.5,0.2,0.1 V)首次循环的交流阻抗谱及其相应的拟合曲线
Fig. 3 Electrochemical impedance spectroscopy Nyquist plots and fitted curves of natural graphite samples before and after surface-modification at various potentials (0.7, 0.5, 0.2, 0.1 V) for the first cycle
SEI膜在首次嵌锂过程中形成[26]。为了研究H2SO4表面修饰对天然石墨表面SEI膜形成过程及形成后稳定性的影响,考察样品在不同嵌脱锂电压下首次和多次循环后的交流阻抗谱变化。图3所示为天然石墨表面修饰前后样品的交流阻抗谱及相应的拟合曲线。图4所示为拟合采用的交流阻抗电路图。图4中,Re代表电解液阻抗,CSEI代表膜电容,RSEI代表膜阻抗,CPE代表常相角元件,Rct代表电荷转移电阻,Wo代表扩散阻抗,其中Re、CSEI和RSEI出现在高频区,CPE和Rct出现在中频区,Wo出现在低频区[27-29]。由图3可知,拟合曲线和实验曲线几乎重合,说明拟合的交流阻抗电路图是合理的。在大多数研究中只重点讨论了RSEI和Rct的变化,忽略了CSEI和CPE[30-31]。CPE是个较复杂的元件,有些研究中为了简化,用Cdl来取代CPE[32]。本文作者除研究RSEI和Rct外,还对CSEI和CPE进行了讨论,从CPE中提取其电容部分,提取的电容部分CCPE计算公式如下:
(1)
式中:Q为常量;α表示电极表面的极化程度,为0~1之间的无量纲常数,从阻抗图分析得到。该提取方法由HSU等提出[17, 33]。
天然石墨表面修饰前后嵌脱锂过程中不同电压下的交流阻抗参数变化如图5。由图5(a)和(b)可知,NG在嵌锂过程中RSEI呈增加趋势,即由2.050 Ω增加至3.361 Ω,Rct呈减小趋势,即由11.570 Ω减小至7.484Ω;在脱锂过程中RSEI和Rct均呈现增加趋势,即RSEI由2.544 Ω增加至3.918 Ω,Rct由14.610 Ω增加至22.440 Ω。而NGS3在嵌脱锂的过程中的RSEI和Rct几乎恒定不变,RSEI维持在1.468 Ω左右,Rct维持在5.783Ω左右。在相同的嵌脱锂的变化过程中,NGS3的RSEI和Rct均小于NG的,例如嵌锂时在0.5 V电压下,NG对应的RSEI和Rct分别为2.635和8.355 Ω,而NGS3对应的RSEI和Rct分别为1.623和6.631 Ω,说明经H2SO4表面修饰的天然石墨在嵌脱锂过程中能快速形成稳定的SEI膜。
图4 交流阻抗的拟合电路图
Fig. 4 Equivalent circuit used to fit AC impedance Nyquist plots
图5 不同电压下表面修饰前(NG)后(NGS3)天然石墨样品首次嵌脱锂过程中的交流阻抗参数
Fig. 5 AC impedance parameters of natural graphite samples before (NG) and after (NGS3) surface-modification at different voltages during first lithium insertion/de-insertion process
电容器储存电荷的能力与孔结构有关[34],电容的大小可反映存储锂的能力及孔结构数量。由图5(c)和(d)可看出,NG在嵌锂过程中CSEI呈减小趋势,即由5.335 μF减小至3.449 μF,CCPE呈增加趋势,即由21.05 μF增加至28.57 μF;在脱锂过程中CSEI和CCPE均呈减小趋势,即CSEI由2.745 μF减小至1.745 μF,CCPE由8.581 μF减小至4.252 μF。NGS3在嵌锂过程中CSEI和CCPE均呈增加趋势,即CSEI由7.502 μF增加至8.242 μF,CCPE由34.25 μF增加至41.67 μF;在脱锂过程中CSEI和CCPE呈减小趋势,即CSEI由9.059 μF减小至4.447 μF,CCPE由38.38 μF减小至24.40 μF。在同样的嵌脱锂变化过程中,NGS3的CSEI和CCPE均大于NG的,说明经H2SO4表面修饰的天然石墨表面孔结构增加,有利于锂离子的存储,嵌脱锂容量增加,与图2中电化学性能一致。
硫酸表面修饰前后天然石墨经多次循环的交流阻抗谱及RSEI的变化如图6所示。由图6可知,随循环的进行,NGS3的RSEI几乎维持在2.548 Ω左右不变,而NG的RSEI有明显的变化且极其不稳定,由4.323 Ω突增至7.342 Ω,然后减小至5.848 Ω,进一步说明H2SO4表面修饰天然石墨能形成稳定的SEI膜,有利于电化学性能的提高。
2.4 活化能分析
图6 表面修饰前(NG)后(NGS3)天然石墨样品经多次循环后的交流阻抗谱及RSEI
Fig. 6 Electrochemical impedance spectra and RSEI changes of natural graphite samples before (NG) and after (NGS3) surface-modification after manifold cycles
图7 天然石墨在LiPF6/(EC+DMC+EMC)(质量比为1:1:1)的电解液中界面导电率和温度的关系
Fig. 7 Temperature dependence of natural graphite on interfacial conductivity (1/Rct) on in LiPF6/(EC+DMC+EMC) (mass ratio of 1:1:1) electrolytes
活化能可反映出锂离子在天然石墨电极和电解液界面传输的动力学[35]及锂离子从溶剂分子中去溶剂化能力,活化能越低表明去溶剂化能力越弱[32]。为了研究H2SO4表面修饰对天然石墨活化能的影响,测试了表面修饰前后天然石墨样品在嵌锂电压为2.0 V、不同温度(0、15、25和35 ℃)下交流阻抗谱的变化。图7所示为天然石墨在LiPF6/(EC+DMC+EMC)(质量比为1:1:1)的电解液中界面导电率与温度的关系。界面传导率遵循阿累尼乌斯方程式[36]:
(2)
式中:A、Ea、R和T分别代表频率因子、表观活化能、摩尔气体常数和热力学温度。根据式(2)计算得知,NG的Ea为87.7 kJ/mol,NGS3的Ea为77.2 kJ/mol。YAMADA等[32]和ABE等[35]获得的石墨/电解液界面的活化能在50 kJ/mol左右或更高,本研究结果与文献所得的结果基本相符。由活化能结果可知,H2SO4表面修饰降低了界面的活化能,从而提高了锂离子的去溶剂化能力,是电化学性能提高的原因之一。
3 结论
1) H2SO4表面修饰提高了天然石墨的倍率容量和循环性能,在0.2C下的脱锂比容量由311.9增加至339.5 mA·h/g,容量保持率由90.2%增加至93.0%;在0.5C下的脱锂比容量由294.6增加至333.8 mA·h/g,容量保持率由85.2%增加至91.5%,且在0.5C下20次循环后的脱锂容量由299.9增加320.5 mA·h/g。
2) 经H2SO4修饰后的天然石墨表面生成了大量—COO-,有利于快速形成稳定的SEI膜及降低RSEI和Rct。H2SO4表面修饰增加了SEI膜微孔数目,使CSEI和CCPE增大,改善了天然石墨的储锂能力。
3) NG和NGS3样品的Ea分别为87.7和77.2 kJ/mol,表明H2SO4表面修饰有利于提高锂离子从溶剂分子中的去溶剂化能力,改善SEI膜的稳定性,从而提高天然石墨的电化学性能。
REFERENCES
[1] 黄可龙, 王兆翔, 刘素琴. 锂离子电池原理与关键技术[M]. 北京: 化学工业出版社, 2008.
HUANG Ke-long, WANG Zhao-xiang, LIU Su-qing. Principle and key technology of lithium ion battery[M]. Beijing: Chemistry Industry Press, 2008.
[2] YOSHIO M, WANG H Y, FUKUDA K, UMENO T, ABE T, OGUMI Z. Improvement of natural graphite as a lithium-ion battery anode material: From raw flake to carbon-coated sphere[J]. Journal of Materials Chemistry, 2004, 14: 1754-1758.
[3] WU Y P, JIANG C Y, WAN C R, TSUCHIDA E. Composite anode material for lithium ion battery with low sensitivity to water[J]. Electrochemistry Communications 2000, 2(9): 626-629.
[4] WU Y P, JIANG C Y, WAN C R, TSUCHIDA E. Effects of catalytic oxidation on the electrochemical performance of common natural graphite as an anode material for lithium ion batteries[J]. Electrochemistry Communications, 2000, 2(4): 272-275.
[5] PELED E. The electrochemical behavior of alkali and alkaline earth metals in nonaqueous battery systems—Solid electrolyte interphase model[J]. Journal of Electrochemical Society, 1979, 126(12): 2047-2051.
[6] 吴宇平, 袁翔云, 董 超, 段冀渊. 锂离子电池——应用与实践[M]. 2版. 北京: 化学工业出版社, 2012: 59.
WU Yu-ping, YUAN Xiang-yun, DONG Chao, DUAN Ji-yuan. Lithium ion battery——Application and practice[M]. 2nd ed. Beijing: Chemistry Industry Press, 2012: 59.
[7] WU Y P, JIANG C Y, WAN C R, HOLZE R. Mild preparation of anode materials by a salt-free green method[J]. Electrochemistry Communications, 2002, 4(6): 483-487.
[8] PELED E, MENACHEM C, BAR-TOW D, MELMAN A. Improved graphite anode for lithium-ion batteries chemically bonded solid electrolyte interface and nanochannel formation[J]. Journal of Electrochemical Society, 1996, 143(1): L4-L7.
[9] MENACHEM C, PELED E, BURSTEIN L, ROSENBERG Y. Characterization of modified NG7 graphite as an improved anode for lithium-ion batteries[J]. Journal of Power Sources, 1997, 68(2): 277-282.
[10] BUQA H, GOLOB P, WINTER M, BESENHARD J O. Modified carbons for improved anodes in lithium ion cells[J]. Journal of Power Sources, 2001, 97/98: 122-125.
[11] WU Y P, JIANG C Y, WAN C R, TSUCHIDA E. A green method for the preparation of anode materials for lithium ion batteries[J]. Journal of Materials Chemistry, 2001, 11: 1233-1236.
[12] WU Y P, JIANG C Y, WAN C R, HOLZE R. Modified natural graphite as anode material for lithium ion batteries[J]. Journal of Power Sources, 2002, 111(2): 329-334.
[13] ZHAO Hai-peng, REN Jian-guo, HE Xiang-ming, LI Jian-jun, JIANG Chang-yin, WAN Chun-rong. Modification of natural graphite for lithium ion batteries[J]. Solid State Sciences, 2008, 10(5): 612-617.
[14] WU Y P, JIANG C Y, WAN C R, HOLZE R. Anode materials for lithium ion batteries by oxidative treatment of common natural graphite[J]. Solid State Ionics, 2003, 156(3/4): 283-290.
[15] 高文超, 黄 桃, 沈宇栋, 余爱水. 酚醛树脂包覆氧化天然石墨作为锂离子电池负极材料[J]. 物理化学学报, 2011, 27(9): 2129-2134.
GAO Wen-chao, HUANG Tao, SHEN Yu-dong, YU Ai-shui. Phenolic resin coated natural graphite oxide as an anode material for lithium ion batteries[J]. Acta Physico-Chimica Sinica, 2011, 27(9): 2129-2134.
[16] HIRSCHORN B, ORAZEM E M, TRIBOLLET B, VIVIER V, FRATEUR I, MUSIANI M. Constant-phase-element behavior caused by resistivity distributions in films[J]. Journal of Electrochemical Society, 2010, 157(12): C452-C457.
[17] HIRSCHORN B, ORAZEM E M, TRIBOLLET B, VIVIER V, FRATEUR I, MUSIANI M. Constant-phase-element behavior caused by resistivity distributions in films[J]. Journal of Electrochemical Society, 2010, 157 (12): C458-C463.
[18] ZHANG S S, XU K, JOW T R. EIS study on the formation of solid electrolyte interface in Li-ion battery[J]. Electrochimica Acta, 2006, 51(8/9): 1636-1640.
[19] 马文石, 周俊文, 林晓丹. 乙醇胺功能化石墨烯的制备与表征[J]. 化学学报, 2011, 69(12): 1463-1468.
MA Wen-shi, ZHOU Jun-wen, LIN Xiao-dan. Preparation and characterization of functionalized graphene with ethanolamine[J]. Acta Chimica Sinica, 2011, 69(12): 1463-1468.
[20] 刘玲玲, 武彦文, 张 旭, 欧阳杰, 李冰宁, 侯 敏, 陈舜琮. 傅里叶变换红外光谱结合模式识别法快速鉴别食用油的真伪[J]. 化学学报, 2012, 70(8): 995-1000.
LIU Lin-lin, WU Yan-wen, ZHANG Xu, OUYANG Jie, LI Bing-ning, HOU Ming, CHEN Shun-cong. Application of Fourier transform infrared spectroscopy combined with pattern recognition method for rapid authentication of edible oil[J]. Acta Chimica Sinica, 2012, 70(8): 995-1000.
[21] 邹艳红, 吴 婧, 刘洪波, 陈宗璋. 聚苯胺/氧化石墨的合成及其在DNA识别上的应用[J]. 新型炭材料, 2005, 20(4): 360-364.
ZOU Yan-hong, WU Jing, LIU Hong-bo, CHEN Zong-zhang. Preparation of polyaniline-intercalated graphite oxide composite and its application in detecting DNA[J]. New Carbon Materials, 2005, 20(4): 360-364.
[22] 肖跃龙, 戴 璇, 张 翼, 徐 行, 刘洪涛, 潘春跃. 红外光谱法对六氟磷酸锂的快速定量分析[J]. 分析科学学报, 2012, 28(3): 357-360.
XIAO Yue-long, DAI Xuan, ZHANG Yi, XU Hang, LIU Hong-bo, PAN Chun-yue. Rapid quantitative analysis of lithium hexafluorophosphate by infrared spectroscopy[J]. Journal of Analytical Science, 2012, 28(3): 357-360.
[23] WU Y P, JIANG C, WAN C, HOLZE R. Effects of pretreatment of natural graphite by oxidative solutions on its electrochemical performance as anode material[J]. Electrochim Acta, 2003, 48: 867-874.
[24] AURBACH D. Review of selected electrode-solution interactions which determine the performance of Li and Li ion batteries[J]. Journal of Power Sources, 2000, 89(2): 206-218.
[25] LU M, CHENG H, YANG Y. A comparison of solid electrolyte interphase (SEI) on the artificial graphite anode of the aged and cycled commercial lithium ion cells[J]. Electrochimica Acta, 2008, 53(9): 3539-3546.
[26] GUO Kun-kun, PAN Qin-min, FANG Shi-bi. Poly (acrylonitrile) encapsulated graphite as anode materials for lithium ion batteries[J]. Journal of Power Sources, 2002, 111(2): 350-356.
[27] LIU Ping, WU Hao-qing. Construction and destruction of passivating layer on LixC6 in organic electrolytes: an impedance study[J]. Journal of Power Sources, 1995, 56(1): 81-85.
[28] ANDREA D, MEILER M, STEINER K, WIMMER CH, SOCZKA-GUTHA T, SAUER D U. Characterization of high-power lithium-ion batteries by electrochemical impedance spectroscopy. I: Experimental investigation[J]. Journal of Power Sources, 2011, 196(12): 5334-5341.
[29] MOMMAT, MATSUNAGA M, MUKOYAMA D, OSAKA T. AC impedance analysis of lithium ion battery under temperature control[J]. Journal of Power Sources, 2012, 216: 304-307.
[30] ITAGAKI M, KOBARIN, YOTSUDA S, WATANABE K, KINOSHITA S, UE M. In-situ electrochemical impedance spectroscopy to investigate negative electrode of lithium-ion rechargeable batteries[J]. Journal of Power Sources, 2004, 135(1/2): 255-261.
[31] GUO J C, SUN A, CHEN X L, WANG C S, MANIVANNAN A. Cyclability study of silicon-carbon composite anodes for lithium-ion batteries using electrochemical impedance spectroscopy[J]. Electrochimica Acta, 2011, 56(11): 3981-3987.
[32] YAMADA Y, IRIYAMA Y, ABE T, OGUMI Z. Kinetics of lithium ion transfer at the interface between graphite and liquid electrolytes: Effects of solvent and surface film[J]. Langmuir 2009, 25(21): 12766-12770.
[33] HSU H C, MANSFELD F. Technical note: Concerning the conversion of the constant phase element parameter Y0 into a capacitance[J]. Corrosion, 2001, 57(9): 747-748.
[34] SHUKLA A K, SAMPATH S, VIJAYAMOHANAN K. Electrochemical supercapacitors: Energy storage beyond batteries[J]. Current Science, 2000, 79(12): 1656-1661.
[35] ABE T, FUKUDA H, IRIYAMA Y, OGUMI Z. Solvated Li-ion transfer at interface between graphite and electrolyte[J]. Journal of Electrochemical Society, 2004, 151(8): A1120-A1123.
[36] YAMADA Y, IRIYAMA Y, ABE T, OGUMI Z. Kinetics of electrochemical insertion and extraction of lithium ion at SiO[J]. Journal of Electrochemical Society, 2010, 157(1): A26-A30.
(编辑 陈卫萍)
基金项目:教育部留学回国人员科研启动基金资助项目([2011]1139);湖南省研究生科研创新项目(CX2012B370);大学生研究性学习与创新性实验计划项目(201210536049)
收稿日期:2013-03-25;修订日期:2013-10-26
通信作者:陈召勇,教授,博士;电话:0731-85258224;E-mail:chenzhaoyongcioc@126.com