Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-Ion Electrode Performance

Author(s): Liu, G; Zheng, H; Song, X; Battaglia, VS | Abstract: This paper investigates lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation. There are three essential components in a positive electrode laminate: active material (AM) particles, acetylene black (AB) particles, and the polymer binder. The high filler content and discrete particle sizes make the electrode laminate a very unique polymer composite. This work introduces a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces. This competition leads to the observed variations in electrode morphology and performance for different electrode formulations. The electronic conductivities of the cathode laminates were measured and compared to an effective conductivity calculation based on the physical model to probe the interaction among the three components to reveal the critical factors controlling electrode conductivity and electrochemical performance. The data and effective conductivity calculation results agree very well with each other. This developed physical model provides a theoretical guideline for optimization of electrode composition for most polymer binder-based Li-ion battery electrodes. © 2012 The Electrochemical Society.

[1]  J. Wolfenstine.  Charge compensation in LiCoO2 , 2004 .

[2]  A. West,et al.  Electronic Conductivity of LiCoO2 and Its Enhancement by Magnesium Doping , 1997 .

[3]  E. Dannenberg.  Bound Rubber and Carbon Black Reinforcement , 1986 .

[4]  Venkat Srinivasan,et al.  Optimization of Lithium Titanate Electrodes for High-Power Cells , 2006 .

[5]  J. Dahn,et al.  Structure, Electrochemical Properties, and Thermal Stability Studies of Li [ Ni0.2Co0.6Mn0.2 ] O2 Effect of Synthesis Route , 2005 .

[6]  A. Medalia.  Morphology of aggregates: VI. Effective volume of aggregates of carbon black from electron microscopy; Application to vehicle absorption and to die swell of filled rubber , 1970 .

[7]  P. B. Lindley,et al.  The mechanical fatigue limit for rubber , 1965 .

[8]  W. M. Hess,et al.  Carbon-black-elastomer interaction , 1991 .

[9]  R. D. Heidenreich,et al.  A test object and criteria for high resolution electron microscopy , 1968 .

[10]  M. Sumita,et al.  Morphology, crystallization and melting behaviors of isotactic polypropylene/high density polyethylene blend: effect of the addition of short carbon fiber , 2000 .

[11]  Xiangyun Song,et al.  Cathode Performance as a Function of Inactive Material and Void Fractions , 2010 .

[12]  Andrew M. Minor,et al.  Optimization of Acetylene Black Conductive Additive and PVDF Composition for High-Power Rechargeable Lithium-Ion Cells , 2007 .

[13]  C. M. Blow.  Polymer/particulate filler interaction—the bound rubber phenomena , 1973 .

[14]  Z. Rigbi,et al.  Carbon black filled natural rubber. 1. Structural investigations , 1991 .

[15]  C. Chan,et al.  Distribution of carbon black in semicrystalline polypropylene studied by transmission electron microscopy , 2002 .

[16]  Herbert L Case,et al.  Calendar- and cycle-life studies of advanced technology development program generation 1 lithium-ion batteries , 2002 .

[17]  J. Jog,et al.  Poly(vinylidene fluoride)/clay nanocomposites prepared by melt intercalation: Crystallization and dynamic mechanical behavior studies , 2002 .

[18]  Andrew M. Minor,et al.  Effects of Various Conductive Additive and Polymeric Binder Contents on the Performance of a Lithium-Ion Composite Cathode , 2008 .