Some suppliers of battery surface analysis equipment Germany Hitachi Hightech +49 2151 643 50 www.hitachi-hightech.com Horiba Europe +49 6172 1396 0 www.horiba.com UK Blue Scientific +44 1223 422269 www.blue-scientific.com Kratos Analytics +44 161 888 4400 www.kratos.com Hiden Analytical +44 1925 445225 www.hidenanalytical.com USA Jeol +1 978 535 5900 www.jeol.com Nanoscience Instruments +1 480 758 5400 www.nanoscience.com Thermo Fisher Scientific +1 781 622 1000 www.thermofisher.com Battery surface analysis | Focus E-Mobility Engineering | September/October 2023 39 LiCoO2 has served as the archetypical cathode material for rechargeable lithium-ion batteries since the 1980s, and five different lots of LiCoO2 used as cathode material were analysed on a laser diffraction particle size analyser. The powder was dispersed in water containing 0.2% sodium hexametaphosphate, and laser diffraction was used for pass/ fail testing to determine if the material met the incoming material particle size specification. Companies with multiple sites often need to compare data from their different laboratories. Samples of lithium manganese oxide and lithium titanate were analysed on two different systems in order to quantify the instrument-to-instrument agreement. The laser diffraction systems have high levels of reproducibility and agreement between systems when measuring the PSD of several battery materials. The researchers used ultrasound to disperse the LiMn2O4 in deionised (DI) water containing 0.2% sodium hexametaphosphate to improve the measurement process. The sample was analysed without ultrasound, and then with 1, 3, and 5 minutes of it, with 3 minutes being the optimum time. Lithium titanate Li2TiO3 is often used as the anode material for fast-recharging lithium titanate batteries. Again, ultrasound was used to disperse the lithium titanate in DI water containing 0.2% sodium hexametaphosphate and the samples were analysed without ultrasound, and then with 3 minutes of ultrasound. This time the dispersion of the sample did not improve with the addition of ultrasound. Light scattering Polarised imaging dynamic light scattering (PIDLS) is another technique for measuring the size of nanoparticles and their shape, as well as distribution in battery materials. A dimensionless quantity called optical sphericity is used to describe the degree of deviation of nanoparticles from spheres. This method will greatly contribute to in-situ synthesis, structure-function analysis, and quality assessment of nanoparticles. The performance of nanoparticles is often influenced by factors such as particle size and shape. Traditionally, electron microscopy or atomic force microscopy is used to analyse the size and shape of nanoparticles, but this has challenges such as complex sample preparation, time-consuming processing, and difficulties in achieving quantitative characterisation. Unlike the electron microscopy and atomic force microscopy methods, the PIDLS method does not directly measure the nanoparticle size and morphology. It is a combination of the imaging dynamic light scattering (IDLS) and polarised light scattering (PLS) methods. By illuminating a sample of nanoparticles with a polarised laser beam, a camera with a polarised filter receives the scattered light and obtains scattering images in the 0, 45, 90 and 135o polarisation directions. Owing to the continuous random (Brownian) motion of the particles, the spatial positions and orientations of the particles vary constantly, resulting in fluctuations in the intensity and polarisation state of the scattered light. The rate of intensity fluctuations in the scattered light is related to the XRF analysis can be carried out on battery production lines using handheld equipment (Courtesy of Hitachi Hightech)
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