•  
  •  
 

Corresponding Author

Shi-Jun LIAO(chsjliao@scut.edu.cn)

Abstract

In this work, the LiFePO4/C composites were prepared by the spray drying and carbothermal method, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements. The effects of the organic assisted templates on the morphologies and electrochemical properties of the LiFePO4/C composites were investigated. The results showed that the morphology and microstructure of the composites could be tuned by incorporating with the different templates. The morphology of the composite appeared to be solid microspheres if no organic template was added, while porous microspheres, nest-like aggregation, and uniform nano-micro spheres, if citric acid, glucose, and PVA were used as the templates, respectively. Among all the samples, the composite prepared with PVA as a template also exhibited the best properties in batteries, including the highest tap density, the lowest charge transfer resistances and the highest capacities. The best discharge capacities were measured to be 156.7 and 92.1 mAh?g–1 at 0.1 and 5.0 C rate, respectively. The obvious charge-discharge plateaus at high rates and excellent cycling performance at various rates were achieved.

Graphical Abstract

Keywords

cathode materials, spray drying, assisted template, PVA

Publication Date

2012-02-28

Online Available Date

2011-10-30

Revised Date

2011-09-26

Received Date

2011-09-06

References

[1] Padhi A K, Nanjundaswamy K S, Goodenough J B. Phospho-olivines as positive-electrode materials for rechargeable lithium batteries [J]. J Electrochem Soc, 1997, 144(4): 1188-1194.

[2] Padhi A K, Nanjundaswamy K S, Masquelier C, et al. Effect of structure on the Fe3+/Fe2+ redox couple in iron phosphates [J]. J Electrochem Soc, 1997, 144(5): 1609-1613.

[3] Chung S Y, Bloking J T, Chiang Y M. Electronically conductive phospho-olivines as lithium storage electrodes [J]. Nat Mater, 2002, 1(2): 123-128.

[4] Prosini P P, Lisi M, Zane D, et al. Determination of the chemical diffusion coefficient of lithium in LiFePO4 [J]. Solid State Ionics, 2002, 148(1-2): 45-51.

[5] Chen Z H, Dahn J R. Reducing carbon in LiFePO4/C composite electrodes to maximize specific energy, volumetric energy, and tap density [J]. J Electrochem Soc, 2002, 149(9): A1184-A1189.

[6] Choi D, Kumta P N. Surfactant based sol-gel approach to nanostructured LiFePO4 for high rate Li-ion batteries [J]. J Power Sources, 2007, 163(2): 1064-1069.

[7] Delacourt C, Poizot P, Levasseur S, et al. Size effects on carbon-free LiFePO4 powders [J]. Electrochem Solid St, 2006, 9(7): A352-A355.

[8] Zheng Ming-sen(郑明森), Liu Shan-ke(刘善科), Sun Shi-gang(孙世刚), et al. Cu doping LiFePO4 and its electrochemical performance [J]. Electrochemistry(电化学), 2008, 14(1): 1-5.

[9] Lu J B, Tang Z L, Le B, et al. Structure and electrochemical properties of LiFePO4 as the cathode of lithium ion battery [J]. Chem J Chinese U(高等化学学报), 2005, 26(11): 2093-2096.

[10] Dominko R, Bele M, Gaberscek M, et al. Porous olivine composites synthesized by sol-gel technique [J]. J Power Sources, 2006, 153(2): 274-280.

[11] Cai Y, Li Z J, Zhang H L, et al. 1-Alkyl-2,3-dimethylimidazolium bis (trifluoromethanesul -fonyl) imide ionic liquids as highly safe electrolyte for Li/LiFePO4 battery [J]. Electrochim Acta, 2010, 55(16): 4728-4733.

[12] Zou Hong-li(邹红丽), Zhang Guang-hui(张光辉), Shen Pei-kang(沈培康). Hydrothermal reduction synthesis of LiFePO4 and its electrochemical performance [J]. Electrochemistry(电化学), 2010, 16(4): 416-419.

[13] Saravanan K, Reddy M V, Balaya P, et al. Storage performance of LiFePO4 nanoplates [J]. J Mater Chem, 2009, 19(5): 605-610.

[14] Xu C B, Lee J, Teja A S. Continuous hydrothermal synthesis of lithium iron phosphate particles in subcritical and supercritical water [J]. J Supercrit Fluid, 2008, 44(1): 92-97.

[15] Gomez L S, de Meatza I, Martin M I, et al. Morphological, structural and electrochemical properties of lithium iron phosphates synthesized by Spray Pyrolysis [J]. Electrochim Acta, 2010, 55(8): 2805-2809.

[16] Xie H, Zhou Z T. Physical and electrochemical properties of mix-doped lithium iron phosphate as cathode material for lithium ion battery [J]. Electrochim Acta, 2006, 51(10): 2063-2067.

[17] Yu F, Zhang J J, Yang Y F, et al. Preparation and characterization of mesoporous LiFePO4/C microsphere by spray drying assisted template method [J]. J Power Sources, 2009, 189(1): 794-797.

[18] Yu F, Zhang J J, Yang Y F, et al. Up-scalable synthesis, structure and charge storage properties of porous microspheres of LiFePO4@C nanocomposites [J]. J Mater Chem, 2009, 19(48): 9121-9125.

[19] Ju S H, Kang Y C. LiFePO4/C cathode powders prepared by spray pyrolysis from the colloidal spray solution containing nano-sized carbon black [J]. Mater Chem Phys, 2008, 107(2-3): 328-333.

[20] Konstantinov K, Bewlay S, Wang G X, et al. New approach for synthesis of carbon-mixed LiFePO4 cathode materials [J]. Electrochim Acta, 2004, 50(2-3): 421-426.

[21] Bewlay S L, Konstantinov K, Wang G X, et al. Conductivity improvements to spray-produced LiFePO4 by addition of a carbon source [J]. Mater Lett, 2004, 58(11): 1788-1791.

[22] Dominko R, Bele M, Goupil J M, et al. Wired porous cathode materials: A novel concept for synthesis of LiFePO4 [J]. Chem Mater, 2007, 19(12): 2960-2969.

[23] Hu Y S, Guo Y G, Dominko R, et al. Improved electrode performance of porous LiFePO4 using RuO2 as an oxidic nanoscale interconnect [J]. Adv Mater, 2007, 19(15): 1963-1966.

[24] Jiang T, Pan W, Wang J, et al. Carbon coated Li3V2(PO4)3 cathode material prepared by a PVA assisted sol-gel method [J]. Electrochim Acta, 2010, 55(12): 3864-3869.

[25] Huang B, Zheng X D, Jia D M, et al. Design and synthesis of high-rate micron-sized, spherical LiFePO4/C composites containing clusters of nano/microspheres [J]. Electrochim Acta, 2010, 55(3): 1227-1231.

[26] Hwang B J, Hsu K F, Hu S K, et al. Template-free reverse micelle process for the synthesis of a rod-like LiFePO4/C composite cathode material for lithium batteries [J]. J Power Sources, 2009, 194(1): 515-519.

[27] Yu F, Zhang J, Yang Y, et al. Porous micro-spherical aggregates of LiFePO4/C nanocomposites: A novel and simple template-free concept and synthesis via sol-gel-spray drying method [J]. J Power Sources, 2010, 195(19): 6873-6878.

[28] Gao F, Tang Z Y. Kinetic behavior of LiFePO4/C cathode material for lithium-ion batteries [J]. Electrochim Acta, 2008, 53(15): 5071-5075.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.