The Influence of Dispersion in Lithium-Ion Battery Performance

What Dispersion Means for Your Battery 

In lithium-ion battery manufacturing, dispersion refers to how evenly the slurry components - graphite, conductive carbon, binders, and thickeners - are distributed. While it may sound like a simple mixing step, dispersion is actually a critical design factor that shapes the electrode’s microstructure and influences: 

  • Electrical conductivity 
  • Mechanical strength 
  • Adhesion to current collectors 

Poor dispersion leads to agglomeration, where particles cluster due to hydrophobic interactions or inadequate stabilization. This results in uneven coatings, unpredictable performance, and premature degradation. These issues often go unnoticed during early testing but emerge over time, affecting reliability, cycle life and customer satisfaction.

Why Dispersion Gets Overlooked 

Dispersion is often treated as a background process, but it’s shaped by a complex interplay of: 

  • Surface chemistry of particles 
  • Behaviour of binders and additives 
  • Shear forces applied during mixing 

For example, carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) are often described as a binder and thickener. In reality, both additives adsorb onto particle surfaces, improving dispersion and suppressing agglomeration (Lim et al., 2015). This affects electrode performance, especially capacity and adhesion strength.

Even the mixing method matters. One study found that simply changing how the negative electrode was mixed doubled the cycle life of a LiCoO₂/graphite battery (Yang et al., 1997). In contrast, another showed that high shear forces can degrade the binder, causing agglomeration and reducing battery performance (Burdette-Trofimov et al., 2021).

Dispersion as a Design Lever 

As the industry pushes toward higher energy densities and more sustainable formulations, dispersion becomes a controllable variable - not just a process step. By understanding and managing dispersion, engineers can unlock: 

  • Greater performance 
  • Improved consistency 
  • Higher process efficiency 

Innovation in this area doesn’t necessarily require new materials - it requires better control of existing ones. Rheological tools can play a critical role in measuring how slurries behave under stress, revealing how well particles are dispersed and the stability of the slurry microstructure.  For example, the storage modulus (G’) of a slurry correlates with interparticle connectivity, particularly among carbon black networks, which influences the dried electrode’s conductivity and overall performance (Reynolds et al., 2024).

Looking Ahead 

Dispersion is fundamental to battery performance. Recognising its role allows manufacturers to design smarter, more reliable electrodes.

Curious about other factors in battery performance? Read our other articles

 

References: 

[1.] S. Lim, S. Kim, K.H. Ahn, S.J. Lee, The effect of binders on the rheological properties and the microstructure formation of lithium-ion battery anode slurries, J. Power Sources 299 (2015) 221–230. https://doi.org/10.1016/j.jpowsour.2015.09.009. 

[2.] C.Y. Yang, C.H. Cheng, S.M. Ho, J.C. Chen, W.M. Hurng, Performance study of the LiCoO2/graphite system, J. Power Sources 68 (1997) 440–442. https://doi.org/10.1016/s0378-7753(97)02590-1. 

[3.] M.K. Burdette-Trofimov, B.L. Armstrong, R.P. Murphy, L. Heroux, M. Doucet, A.M. Rogers, G.M. Veith, Probing Clustering Dynamics between Silicon and PAA or LiPAA Slurries under Processing Conditions, Acs Appl Polym Mater 3 (2021) 2447–2460. https://doi.org/10.1021/acsapm.1c00052. 

[4.] C.D. Reynolds, H. Walker, A. Mahgoub, E. Adebayo, E. Kendrick, Battery electrode slurry rheology and its impact on manufacturing, Energy Adv. 4 (2024) 84–93. https://doi.org/10.1039/d4ya00380b.