Cyclability study of silicon–carbon composite anodes for lithium-ion batteries using electrochemical impedance spectroscopy

• Published in: Electrochimica acta Vol. 56; no. 11; pp. 3981 - 3987
• Main Authors: Guo, Juchen, Sun, Ann, Chen, Xilin, Wang, Chunsheng, Manivannan, Ayyakkannu
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.04.2011; Elsevier
• Subjects: Anodes; Applied sciences; Binders; Carbon fibers; Carbon nanotube; Cycles; Cyclic stability; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Exact sciences and technology; Li-ion battery; Lithium-ion batteries; Multi wall carbon nanotubes; Nanostructure; Silicon anode; Stability; Cyclic stability; Carbon nanotube; Silicon anode; Li-ion battery; Electrochemical impedance spectroscopy; Scanning electron microscopy; Cycling; Stability; Anode; Thermogravimetry; Carbon nanotubes; Nanofiber; Secondary cell; Electrode material; Carbon; Surface structure; Morphology; Composite electrode; Lithion ion batteries; Silicon; Thermal analysis; Electrical characteristic; Modified material
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2011.02.014

► Silicon–carbon anode materials for Li-ion batteries were synthesized. ► Carbonization and annealing processes were used in electrode preparation. ► Capacity fading mechanism was investigated by electrochemical impedance spectroscopy. ► Impedance evolution revealed better stability of the carbonized anode material. The effects of carbonization process and carbon nanofiber/nanotube additives on the cycling stability of silicon–carbon composite anodes were investigated by monitoring the impedance evolution during charge/discharge cycles with electrochemical impedance spectroscopy (EIS). Three types of Si–C anodes were investigated: the first type consisted of Si nanoparticles incorporated into a network of carbon nanofibers (CNFs) and multi-walled carbon nanotubes (MWNTs), with annealed polymer binder. The second type of Si–C anodes was prepared by further heat treatment of the first Si–C anodes to carbonize the polymer binder. The third Si–C anode was as same as the second one except no CNFs and MWNTs being added. Impedance analysis revealed that the carbonization process stabilized the Si–C anode structure and decreased the charge transfer resistance, thus improving the cycling stability. On the other hand, although the MWNTs/CNFs additives could enhance the electronic conductivity of the Si–C anodes, the induced inhomogeneous structure decreased the integrity of the electrode, resulting in a poor long term cycling stability.