Role of PVDF in Rheology and Microstructure of NCM Cathode Slurries for Lithium-Ion Battery

A binder plays a critical role in dispersion of coating liquids and the quality of coating. Poly(vinylidene fluoride) (PVDF) is widely used as a binder in cathode slurries; however, its role as a binder is still under debate. In this paper, we study the role of PVDF on the rheology of cathode battery slurries consisting of Li(Ni1/3Mn1/3Co1/3)O2 (NCM), carbon black (CB) and N-methyl-2-pyrrolidone (NMP). Rheology and microstructure of cathode slurries are systemically investigated with three model suspensions: CB/PVDF/NMP, NCM/PVDF/NMP and NCM/CB/PVDF/NMP. To highlight the role of PVDF in cathode slurries, we prepare the same model suspensions by replacing PVDF with PVP, and we compare the role of PVDF to PVP in the suspension rheology. We find that PVDF adsorbs neither onto NCM nor CB surface, which can be attributed to its poor affinity to NCM and CB. Rheological measurements suggest that PVDF mainly increases matrix viscosity in the suspension without affecting the microstructure formed by CB and NCM particles. In contrast to PVDF, PVP stabilizes the structure of CB and NCM in the model suspensions, as it is adsorbed on the CB surface. This study will provide a useful insight to fundamentally understand the rheology of cathode slurries.

[1]  C. Lee,et al.  Glass ceramic coating on LiNi0.8Co0.1Mn0.1O2 cathode for Li-ion batteries , 2020, Korean Journal of Chemical Engineering.

[2]  Shi-gang Lu,et al.  The effect of solid content on the rheological properties and microstructures of a Li-ion battery cathode slurry , 2020, RSC advances.

[3]  N. Willenbacher,et al.  Effect of Polymeric Binders on Dispersion of Active Particles in Aqueous LiFePO4-Based Cathode Slurries as well as on Mechanical and Electrical Properties of Corresponding Dry Layers , 2020, ACS omega.

[4]  K. Ahn,et al.  How the interaction between styrene-butadiene-rubber (SBR) binder and a secondary fluid affects the rheology, microstructure and adhesive properties of capillary-suspension-type graphite slurries used for Li-ion battery anodes , 2019, Colloids and Surfaces A: Physicochemical and Engineering Aspects.

[5]  K. Ahn,et al.  Effect of neutralization of poly(acrylic acid) binder on the dispersion heterogeneity of Li-ion battery electrodes , 2019, Journal of Materials Science.

[6]  Hanseul Kim,et al.  Hydrophobic Ni-Rich Layered Oxides as Cathode Materials for Lithium-Ion Batteries , 2019, ACS Applied Energy Materials.

[7]  Sangkyun Koo,et al.  Rheological analysis of particle aggregation in a colloidal suspension of carbon black particles , 2018, Korea-Australia Rheology Journal.

[8]  N. Wagner,et al.  Dynamic shear rheology and structure kinetics modeling of a thixotropic carbon black suspension , 2017, Rheologica Acta.

[9]  Joo-Young Lee,et al.  A new paradigm of materials processing—heterogeneity control , 2017 .

[10]  Jiulin Wang,et al.  Effects of binders on the electrochemical performance of rechargeable magnesium batteries , 2017 .

[11]  K. Ahn,et al.  Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films , 2016 .

[12]  Seongmin Ha,et al.  Batteries: Converting to long stability , 2016, Nature Energy.

[13]  H. Pan,et al.  Solvent-Free Manufacturing of Electrodes for Lithium-ion Batteries , 2016, Scientific Reports.

[14]  K. Ahn,et al.  The effect of binders on the rheological properties and the microstructure formation of lithium-ion battery anode slurries , 2015 .

[15]  Jingjie Wu,et al.  Liquid Phase Exfoliation of Two-Dimensional Materials by Directly Probing and Matching Surface Tension Components. , 2015, Nano letters.

[16]  B. Bitsch,et al.  A novel slurry concept for the fabrication of lithium-ion battery electrodes with beneficial properties , 2014 .

[17]  Ming Jia,et al.  A comparative study of different binders and their effects on electrochemical properties of LiMn 2 O 4 cathode in lithium ion batteries , 2014 .

[18]  Y. Song,et al.  Agitation Effect on the Rheological Behavior of Lithium-Ion Battery Slurries , 2014, Journal of Electronic Materials.

[19]  J. Youn,et al.  Evaluation of slurry characteristics for rechargeable lithium-ion batteries , 2013 .

[20]  K. Ahn,et al.  Latex migration in battery slurries during drying. , 2013, Langmuir : the ACS journal of surfaces and colloids.

[21]  J. Youn,et al.  Interaction analysis between binder and particles in multiphase slurries. , 2013, The Analyst.

[22]  Chia‐Chen Li,et al.  Interactions between organic additives and active powders in water-based lithium iron phosphate electrode slurries , 2012 .

[23]  Y. Aoki.  Rheology of carbon black suspensions. IV. Effect of suspending media on the sol–gel transition behavior , 2011 .

[24]  S. Trussler,et al.  A Guide to Li-Ion Coin-Cell Electrode Making for Academic Researchers , 2011 .

[25]  Kyung Hyun Ahn,et al.  Effect of slurry preparation process on electrochemical performances of LiCoO2 composite electrode , 2010 .

[26]  K. Ahn,et al.  Drying of the silica/PVA suspension: effect of suspension microstructure. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[27]  Y. Aoki.  Rheology of Carbon Black Suspensions: Effect of Carbon Black Structure , 2008 .

[28]  Chia-Chen Li,et al.  Improvements of dispersion homogeneity and cell performance of aqueous-processed LiCoO2 cathodes by using dispersant of PAA-NH4 , 2006 .

[29]  Vincent A. Hackley,et al.  Effect of Carboxymethyl Cellulose on Aqueous Processing of Natural Graphite Negative Electrodes and their Electrochemical Performance for Lithium Batteries , 2005 .

[30]  J. Mewis,et al.  A model system for thixotropy studies , 2005 .

[31]  David A Weitz,et al.  Effect of temperature on carbon-black agglomeration in hydrocarbon liquid with adsorbed dispersant. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[32]  Y. Aoki,et al.  Rheology of carbon black suspensions. I. Three types of viscoelastic behavior , 2003 .

[33]  D. Weitz,et al.  Scaling of the viscoelasticity of weakly attractive particles , 2000, Physical review letters.

[34]  D. Rimai,et al.  Fundamentals of adhesion and interfaces , 1995 .