Rate dependence of the reaction mechanism in olivine NaFePO4 Na-ion cathode material

• DOI: 10.1002/er.4078
• Publication Date: 2018-05-10T09:11:28Z
• Authors: Damien Saurel; Montserrat Galceran; Marine Reynaud; Henri Anne; Montse Casas-Cabanas
• Keywords: Cycling

When electrode materials are driven away from equilibrium conditions, significant differences occur in their (dis)charge mechanism. In this paper, the changes phase transformations of olivine NaFePO4 examined as a function cycling rate thorough analyses both voltage-composition profiles galvanostatic cycling, and operando laboratory synchrotron X-ray diffraction experiments. While charge mechanism remains unchanged at all C-rates, high rates enable to unveil 2 concomitant biphasic reactions appearing 3-phase state lower rates. This finding allows rationalising asymmetries observed low rates, which rooted different reaction kinetics.