Typical cathode materials, such as NCA and NMC, are produced through co-precipitation of transition-metal hydroxide precursor materials, followed by calcination (lithiation and oxidation) with a lithium compound. Co-precipitation is a slow process – starting with nucleation, followed by the growth of primary particles, and finally agglomeration to larger secondary particles. The whole process can take anywhere between 20 to 40 hours, depending on process efficiency.
Many parameters – including slurry composition, pH, temperature, and stirring speed – affect co-precipitation efficiency. Optimizing these parameters plays a key role in the quality and throughput of battery cathode precursor materials. To monitor and control them in real-time to improve the efficiency of the co-precipitation process, we offer a range of analytical solutions. What’s more, our solutions can also help you to ensure that your precursor material has the desired properties.
How can I optimize my cathode precursor materials?
Cathode precursor quality and throughput can be optimized by measuring and controlling the following parameters:
Particle size : Precursor particles nucleate, grow and then agglomerate to form larger secondary particles. To ensure the highest production efficiency, these particles should grow above their target size in the minimum possible time. The measurement of particle size over precursor evolution time is therefore an important way to fine-tune process parameters in slurry reactor.
Our online automated Insitec on-line particle size analyzer is ideal for making these measurements in a production environment, delivering real-time analysis every few seconds. Using a feedback loop, this information can be used to adjust parameters like Ph, temperature, or stirring speed. What’s more, it can also ensure synergy with smart-manufacturing process flows. This delivers high returns: typically, a cathode manufacturing plant producing 1000kg of cathode material per day can save up to 200,000 USD per year by analyzing precursor slurry particle size with the Insitec.
Our Mastersizer can also be used to accurately measure particle size distribution for quality control, including in the lab.
Particle shape : Particle shape plays an important role in the formation of stable secondary particles and can significantly influence precursor yield (tap density), as well as the quality of the final cathode material. For example, elongated particles are more likely to break and re-dissolve in a slurry stirred at high speed.
To enable manufacturers to analyze and optimize particle shape, our Morphologi 4 optical imaging tool can be used to measure parameters such as circularity, elongation/aspect ratio, Circular Equivalent (CE) diameter, and transparency, with its fully automated image analysis.
Chemical composition and impurities: To achieve optimal chemical composition in the final cathode materials, it must first be controlled at the precursor level. X-ray fluorescence (XRF), which can analyze chemical composition and impurities from just a few ppm all the way up to 100%, is the best technique for analyzing chemical composition.
Specifically, XRF provides a simpler and more accurate way of measuring elemental composition than inductively coupled plasma (ICP) mass spectrometry, as it does not require any sample dilution or acid digestion. Many leading battery companies use our benchtop Epsilon 4 EDXRF or Zetium WDXRF spectrometers to analyze the composition of their precursor and cathode materials.
Crystalline Phase: Crystalline phase refers to the structure of materials at atomic scale – the scale at which ionic or electronic transport happens or is hindered. The crystalline phase composition of the precursor can provide an early indication of the final cathode material’s quality. To accurately analyze the crystalline phase composition of cathode precursor materials, manufacturers can use our Aeris compact X-ray diffractometer, an easy-to-use instrument with superb data quality.
Zeta potential : The precipitation of particles from the cathode precursor solution relies on primary particles (of 50-100 nm) interacting to form larger secondary particles (of 10-20 µm). Zeta potential can be used to analyze and adjust Ph and temperature values in order to optimize these interactions. Our Zetasizer accurately measures zeta potential, and can also complement your R&D on precursor synthesis.
Solutions for battery research and quality control
Further reading
