Electrochemical Characterization for Optimal Electrode Quality

Slurry Analysis Electrochemical Characterization for Optimal Electrode Quality

2026-01-21 A guest contribution by Ernst Bratz* | Translated by AI 4 min Reading Time

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The electrochemical analysis of battery slurries promises significant efficiency gains in lithium-ion battery development. An integrated measuring system now makes this technology accessible to developers without specialized electrochemistry knowledge.

Electrochemical analysis: With the help of slurry analysis, efficiency in the development of lithium-ion batteries can be increased. Using suitable hardware, developers can determine the ideal ratio between active material and conductive additives.(Image: Hioki) — Electrochemical analysis: With the help of slurry analysis, efficiency in the development of lithium-ion batteries can be increased. Using suitable hardware, developers can determine the ideal ratio between active material and conductive additives.
(Image: Hioki)

Batteries are everywhere today and are an integral part of our lives. Whether in a simple flashlight, smartphone, laptop, or electric car—practically nothing works without batteries anymore. They are even found in pacemakers and other important medical or safety-related systems. They not only store electricity from renewable energy sources but also ensure that our devices function or step in when the power goes out.

Without batteries, a large part of our mobile technological world would be hardly conceivable. In all areas of application, batteries should function efficiently, sustainably, as well as reliably and fail-safe. Extensive testing is therefore required in the development and production of batteries. These tests include various chemical, physical, and electrotechnical methods.

Slurry Processes in Modern Battery Production

Image 1: The slurry process is an essential component of modern battery production.(Image: Hioki) — Image 1: The slurry process is an essential component of modern battery production.
(Image: Hioki)

Known test parameters of batteries include charge/discharge behavior, self-discharge, aging processes, energy retention, performance characteristics, and internal resistance. Another practical yet less known testing area is slurry analysis.

Slurry processes are an essential component of modern battery production. Slurry refers to a viscous paste made of binder, conductive carbon, and solvents (water or organic solvents) used to coat metal foils for electrode production (Image 1). After the coating and drying process, the electrode foils for lithium-ion cells are created.

The challenge lies in the fact that carbon nanotubes (CNTs) exhibit excellent electrical conductivity but tend to agglomerate. Therefore, a homogeneous dispersion in the slurry is crucial for the electrochemical properties of the final battery cell. Slurry analysis makes it possible to evaluate the quality of the electrode paste before further processing. This is an important quality assurance step in the production chain.

In slurry analysis, both the rheological properties (viscosity) and the particle size distribution are examined. However, there has been a gap in electrochemical characterization so far. This gap is closed by the slurry analysis solution SA2634-KIT from Hioki, which enables a direct electrochemical evaluation of the slurry before electrode production.

Complete Electrochemical Analysis of the Battery

Image 2: The system also models an equivalent circuit using EIS data to extract three proprietary parameters.(Image: Hioki) — Image 2: The system also models an equivalent circuit using EIS data to extract three proprietary parameters.
(Image: Hioki)

The system enables a complete electrochemical characterization of battery slurries already in the development and production phase. It helps developers identify the optimal mixing state and determine the ideal ratio between active material and conductive additives.

Based on electrochemical impedance spectroscopy (EIS), the system models an equivalent circuit and extracts three proprietary parameters: DCR, Rratio, and Uniformity. These objective measurements quantify the conductivity properties of lithium-ion battery slurries and replace subjective evaluation methods.

The practical benefit lies in the optimization of R&D processes and production efficiency: High-performance slurries can be identified more quickly, leading to better electrode foils and cells, shorter development cycles, and higher battery yields.

The three key parameters in detail:

DCR (DC Resistance): Quantifies the overall resistance of the slurry suspension.
R_ratio (Resistance Ratio): Determines the proportion of the resistance component of the conductive material in the DCR.
Uniformity: Assesses the homogeneity of the conductive paths and the consistency of the electrode coating.

Uniformity is particularly critical, as uneven coatings can lead to performance losses, reduced efficiency, and potential safety risks due to inhomogeneous ion transfer and conductivity distribution.

The Setup of the Measurement System and Software Integration

Image 3: The system consists of an LCR meter (IM3536), with which the software performs EIS measurements.(Image: Hioki) — Image 3: The system consists of an LCR meter (IM3536), with which the software performs EIS measurements.
(Image: Hioki)

Image 4: The one for the LCR meter, to hold the electrode cells with the actual material samples.(Image: Hioki) — Image 4: The one for the LCR meter, to hold the electrode cells with the actual material samples.
(Image: Hioki)

The Japanese measurement technology specialist Hioki (distributed by Meilhaus Electronic) has expanded its portfolio to include battery measurement technology and now offers a complete solution for electrochemical slurry analysis. The system is based on an LCR meter (IM3536) that performs electrochemical impedance spectroscopy measurements (EIS) via the corresponding software. On the hardware side, the system includes a special holder on the LCR meter that accommodates electrode cells with the material samples to be analyzed.

The Windows-based analysis program SA2634 was specifically developed for slurry analysis and complements the LCR meter with advanced evaluation functionalities. A key feature is the Nyquist representation (Cole-Cole plot), where developers can directly read the characteristic properties of the individual slurry components:

Binder solution,
Conductive additives and
Active electrode material.

The curve progression in the Nyquist diagram provides direct insight into the electrochemical properties and interactions of the various material components. This enables a well-founded assessment of slurry quality even before electrode production. The integrated system thus offers a seamless measurement chain from hardware acquisition to detailed data analysis.

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Date: 08.12.2025

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Practical Application

Image 5: Practical use is simple. For this purpose, 1 ml of the slurry to be examined is filled into the sample holder/electrode cell.(Image: Hioki) — Image 5: Practical use is simple. For this purpose, 1 ml of the slurry to be examined is filled into the sample holder/electrode cell.
(Image: Hioki)

The measurement process is straightforward and standardizable. First, one milliliter of the slurry to be characterized is filled into a disposable electrode cell. The sample holders are available in packs of 50 and ensure reproducible measurement conditions. The filled sample holder is then inserted into the system holder and fixed to the LCR meter (IM3536). The LCR meter is connected to a PC via USB or Ethernet.

The SA2634 software controls the LCR meter and automatically performs an EIS sweep (electrochemical impedance spectroscopy), capturing impedance spectra over a defined frequency range. After the measurement, the software automatically calculates the characteristic parameters DCR, R_ratio, and Uniformity from the impedance data and generates the corresponding equivalent circuit diagram. The transformation of raw impedance spectra into practically relevant parameters is the crucial factor in this process.

A key advantage of the system is that no advanced EIS knowledge is required from the user. The complex impedance analysis is fully automated by the software and converted into directly interpretable quality parameters for slurry evaluation, making it accessible even for developers without specialized electrochemistry expertise. (heh)

Ernst Bratz works at Meilhaus Electronic.