Sodium Intercalation Mechanism of 3.8 V Class Alluaudite Sodium Iron Sulfate
Year: 2016
Type: article
Abstract: Alluaudite sodium iron sulfate Na2+2xFe2–x(SO4)3 is one of the most promising candidates for a Na-ion battery cathode material with earth-abundant elements; it exhibits the highest potential among any Fe3+/Fe2+ redox reactions (3.8 V vs Na/Na+), good cycle performance, and high rate capability. However, the reaction mechanism during electrochemical charging/discharging processes is still not understood. Here, we surveyed the intercalation mechanism via synchrotron X-ray diffraction (XRD), 23Na nuclear magnetic resonance (NMR), density functional theory (DFT) calculations, X-ray absorption near edge structure (XANES), and Mössbauer spectroscopy. Throughout charging/discharging processes, the structure undergoes a reversible, single-phase (solid solution) reaction based on a Fe3+/Fe2+ redox reaction with a small volume change of ca. 3.5% after an initial structural rearrangement upon the first charging process, where a small amount of Fe irreversibly migrates from the original site to a Na site. Sodium extraction occurs in a sequential manner at various Na sites in the structure at their specific voltage regions.
Source: Chemistry of Materials
Institutions: The University of Tokyo, University of Cambridge, Kyoto University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: Next level real-time characterisation of Li- and Na-ion batteries by – Automatic Tuning Matching Cycler (plus Goniometer) – ATMC(+G) in situ NMR, Development of advanced energy storage system based on overall strategies on new materials and new interface, Pushing the Envelope of Nuclear Magnetic Resonance Spectroscopy for Paramagnetic Systems. A Combined Experimental and Theoretical Approach, G963449153
OpenAlex ID: W2460262146