INDUSTRY NEWS
Empowering Battery Research and Production with Advanced Analytical Solutions Source: ATA Scientific Pty Ltd Lithium-ion (Li-ion) batteries are predicted to play a key role in the trend toward renewable and sustainable industrial electrification solutions. As fossil fuels are phased out and CO2 regulations become more stringent, the increase in demand to provide ever more lightweight, low-cost, safe, high-power and fastcharging batteries has accelerated advances in battery technology. Access to the right tools and technologies can help optimise R&D and production cycles, investigate causes of battery failure, improve safety, and speed up time-to-market, to keep technological progress moving in sync with modern global demands. Here we discuss a complementary set of physical, chemical, and structural analysis solutions designed to enable rapid, high-precision analysis of particle size and shape distribution plus elemental composition of battery materials for the entire process from research through to production.
Measuring Particle Size – Why is it Important? The performance of a battery can be characterised according to the amount of energy that it can store or the amount of power that it can produce. The maximum battery power can be increased by decreasing the particle size of the electrode material and
increasing the surface area. Battery power is determined by the rate of reaction between the electrodes and the electrolyte, while storage capacity is a function of the volume of electrolyte within the cell. These properties are intrinsically linked to the intercalation structure and particle size of the electrode particles, which determine how well the mobile ions are taken up and released by the electrode. Particle size distribution and particle shape influence particle packing, hence the volume of electrolyte that can be accommodated within the interstitial voids of the electrode, which affects storage capacity. As a result, a mixture of coarse and fine particles is often used in the electrodes to increase surface area, whilst also controlling the overall packing fraction of the electrode material to allow good contact between the electrode and the electrolyte. Particle sizing of electrode materials is commonly performed using the Mastersizer 3000 which uses automated laser diffraction technology. With a measurement range that runs from 0.01 to 3500 µm, the Mastersizer is the particle sizing technology of choice for most battery manufacturing applications – starting from precursor to the final milled electrode materials. The Malvern Insitec online process systems deliver real-time monitoring of particle size for automated process
control. These can be used for either the monitoring of particle size evolution in precursor slurry or in the control of electrode material size right after the mill. Smaller particles in electrode slurry production can be prone to agglomeration and/or flocculation, resulting in uneven electrode coatings and ultimately compromising the electrochemical performance. Aggregation and stability can be monitored by measuring zeta potential (particle charge) using the Malvern Zetasizer Ultra. A low zeta potential will indicate particles likely to aggregate whereas a high zeta potential will form a stable dispersion. The Malvern Zetasizer Ultra builds on the legacy of the industry-leading Zetasizer Nano Series adding high-resolution sizing (Multi-Angle Dynamic Light Scattering) and particle concentration capabilities.
Measuring Porosity - Why is it Important? Porosity is an important parameter both for the separator and for the electrolyte to transport lithium-ions between the anode and cathode. By controlling porosity, higher intra-electrode conductivity can be achieved to ensure adequate electron exchange as well as sufficient void space for electrolyte access/transport of lithium-ions for intercalation of the cathode. Higher porosity means less heat generated in the cell and greater
Figure 1 shows a typical manufacturing process for Li-ion batteries. The anode and cathode active materials are processed into a slurry before coating, calendaring, and drying. Uniform dispersion of the solid content (active materials) with minimal agglomeration is critical for a highquality final product.
28 | APRIL 2022
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