Lin Jiang, R&D staff scientist at Thermo Fisher Scientific, reports on a study of oxyfluoride disordered rock-salt (DRX) cathodes as a candidate for a next-generation battery material for EVs that could offer higher energy density. The research team was able to map fluorine atoms without damaging them by using electron microscopy technologies.
Scientists are working on increased demand for batteries with higher energy density that can charge faster and last longer, especially as battery-powered transportation becomes mainstream.
The EV market is the primary driver of higher performance batteries. According to a McKinsey & Company report earlier this year on the mobility industry, batteries for mobility applications such as EVs will account for the majority of demand by 2030.
While lithium-ion batteries have provided sufficient battery power for nearly a century, scientists across academia and industry are looking for ways to meet this increased demand for higher energy density batteries, while maintaining safety, reliability and sustainability across the supply chain, from raw materials to recycling.
Technology innovation
Scientists search for innovative clean energy battery technologies, mitigating demand for raw materials commonly used in today’s batteries, such as lithium, cobalt and nickel. Lessening environmental impact is a key consideration.
Many EV manufacturers are researching solid-state electrolyte batteries as an environmentally friendly option as they offer higher energy density than traditional lithium-ion batteries and can store more energy with less material. Sodium-based batteries are also being widely studied as an option that could put less pressure on supply chains and the environment.
To better understand new battery chemistries, scientists need to visualise beam-sensitive materials at an atomic level without triggering a combustion that would threaten the integrity of the delicate material.
Low electron beam dose imaging is often used to get these atomic images, but it is a balancing act between precision and preservation as scientists work to characterise the materials. However, innovative technologies such as advanced electron microscopy can help with imaging and analysis of these delicate materials.
Atomic level insights
A research team based at the Pacific Northwest National Laboratory in the US has studied oxyfluoride disordered rock-salt (DRX) cathodes as a candidate for a next-generation battery material for EVs that could offer higher energy density compared to traditional cobalt cathodes.
The research found that adding a small amount of fluorine, an element that is difficult to accurately characterise at the atomic level without damaging the atoms, could enhance the capacity and lifespan of the DRX cathodes. They used transmission electron microscopy (TEM) techniques to achieve a scale that can clearly identify concentration, spatial distribution and electronic structure of the fluorine atoms within the DRX lattices.
This led to their discovery that replacing oxygen with fluorine in the DRX cathodes helps to reduce the oxygen loss and enhance redox capacity, making the cathode last longer.
Moving forward
As EV demand and battery power continue to rise, scientists across the battery industry are exploring alternative materials, such as DRX cathodes, for energy dense batteries that are more cost-efficient, safer and sustainable.
While the PNNL research team used both spectroscopic and microscopic techniques on a scanning TEM, there are several innovative technologies and analytical solutions helping scientists learn more about new materials for energy dense batteries, such as electron microscopy, spectroscopy, inductively coupled plasma mass spectrometry (ICP), Fourier transform infrared (FTIR), Raman, X-ray fluorescence (XRF) and chromatography.
Regardless of material, researchers need technologies that allow them to visualise delicate materials at an atomic level to best understand the complexities and structural details. These insights are invaluable and can lead to new chemistries that translate into more sustainable real-world applications. By using a suite of analytical tools, scientists across academia and industry can explore new battery technologies for cleaner energy solutions.
About the author:
Dr. Lin Jiang is a staff scientist in R&D at Thermo Fisher Scientific, specialising in advancing Transmission Electron Microscopy (TEM) technology to address scientific challenges in energy materials. Prior to that, he conducted postdoctoral research at UC Davis/ Irvine and Berkely National Lab, where he gained extensive expertise in utilising Cs-corrected S/TEM, EELS, and in-situ TEM techniques to elucidate the relationship between microstructures and material performance. He has authored over 50 papers and been published in prestigious journals such as Nature Materials and Nature Communications.
