Sumitomo Rubber Industries has long been actively engaged in research involving sulfur, a major raw material in tires that has a significant influence on tire performance as well as performance longevity.
Lithium-sulfur batteries not only have an expected theoretical capacity that is six to seven times greater than conventional lithium-ion batteries but are also lighter and safer to use. However, the commercialization of lithium-sulfur batteries has been hindered by their poor cycle life. Improving cycle life will require extremely high-precision measurements of sulfur compounds. And so, our research group set about developing the world’s first “Tender X-Ray Nanoscope” utilizing SPring-8 (synchrotron radiation facility), which enabled us to make use of “coherent Tender X-Rays”. Thanks to this new measuring technology, we have now succeeded in visualizing sulfur compounds at the nanoscale.
Image A (Coherent X-Ray Diffracttion Image) is produced by irradiating sulfur compounds with a coherent tender x-ray beam. Phase retrieval calculations are then used to generate Image B (X-Ray Absorption Image) and Image C (X-Ray Phase Image). This process is then repeated at varying x-ray energies. The visualization of the chemical state of the sulfur compounds is achieved through the combination of around 30 of these images.
Moving forward, we are also planning to utilize the 3GeV-class Synchrotron Radiation Facility “NanoTerasu” (which is scheduled to go online in 2024) for measurements of lithium-sulfur batteries under charge-discharge cycling as part of our ongoing efforts to realize practical applications for this technology in the field of materials development. We also look forward to applying this technology in our tire research activities, including deeper analysis of the crosslink structure of the chemical bonds between rubber and sulfur.
