According to AZO Materials, researchers at Tohoku University have pioneered a novel technique to study metal ion dissolution in lithium-ion battery cathodes. Utilizing Nuclear Magnetic Resonance Imaging (MRI), they were able to observe and analyze the dissolution process in real time, a significant leap forward in battery diagnostics. Their findings, published in Communications Materials, provide valuable insights into battery degradation, with potential applications for improving battery lifespan and safety.
Understanding Metal Ion Dissolution in Lithium-Ion Batteries
Lithium-ion batteries (LIBs) are widely used in electronics and electric vehicles due to their cost efficiency and high-voltage operation. However, repeated use leads to performance degradation, raising safety concerns. A primary cause of this decline is the dissolution of metal ions from the cathode into the electrolyte. This phenomenon has been difficult to study due to the small scale of metal ion loss. Gaining a precise understanding of where, when, and how much dissolution occurs is crucial for enhancing battery performance and longevity.
MRI: A Game-Changer in Battery Diagnostics
MRI technology, widely used in medical imaging, leverages radio waves and magnetic fields to generate detailed scans. In medical applications, gadolinium-based contrast agents enhance visibility by altering the magnetic properties of targeted regions.
Applying this principle, Tohoku University researchers used MRI to track the dissolution of manganese (Mn²⁺) from a LiMn₂O₄ cathode in a commercial LiPF₆ EC: DMC electrolyte. Given its paramagnetic nature, Mn²⁺ increases MRI signal intensity, making its movement within the battery visible in real time.
Key Findings from the Study
- High Sensitivity Detection: The study demonstrated that even minuscule amounts of dissolved Mn²⁺ can be detected via MRI with high sensitivity.
- Potential for Battery Material Optimization: By monitoring dissolution under different conditions, researchers can evaluate and develop more stable battery chemistries.
- Suppression of Manganese Dissolution: An alternative LiTFSI MCP electrolyte, developed by the MEET Battery Research Center at the University of Münster, Germany, was tested for its ability to prevent Mn²⁺ dissolution.
- Improved Electrolyte Performance: MRI scans showed no significant increase in signal intensity when using LiTFSI MCP, suggesting a suppression of Mn²⁺ dissolution and a more stable electrolyte system.
Future Implications for Battery Research
This innovative MRI-based technique opens new possibilities for investigating battery degradation and testing alternative materials under real-world conditions. Researcher Nithya Hellar emphasized that their findings could help resolve a longstanding question in battery science: “We believe the method developed here can answer the long-time unanswered question of when, where, and how the metal ion dissolution occurs in the lithium-ion battery electrode and can be extended to other electrochemical systems..”
Conclusion
With lithium-ion batteries powering the modern world, ensuring their longevity and safety is paramount. Tohoku University’s cutting-edge research provides a new tool for diagnosing and mitigating battery degradation, potentially leading to more efficient and durable battery technologies in the future.
Reference: Hellar, N., et al. (2025) Direct observation of Mn-ion dissolution from LiMn2O4 lithium battery cathode to electrolyte. Communications Materials. doi.org/10.1038/s43246-025-00733-2.
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