1. Soft X-Ray Microscopy of Manganese Hexacyanoferrate Cathode Materials for Lithium and Sodium Batteries' (ise202741)
- Author
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Li, M., Maisuradze, M., Khan, A., Mullaliu, Angelo, Sorrentino, Andrea, Passerini, Stefano, Giorgetti, Marco, and Tonti, Dino
- Abstract
A very interesting, durable and cheap class of active intercalation cathode materials is represented by open-framework structures such as Prussian blue analogues (PBAs). Manganese hexacyanoferrate (MnHCF) with nominal formula Na2Mn[Fe(CN)6]¿zH2O, only includes abundant elements and is safely and easily synthesized. The material features high specific capacities at high potentials when compared to other PBAs [1]. A combined XAS and XRD study has demonstrated that both Fe and Mn sites are involved in the electrochemical process but a capacity fading is observed during the charge and discharge steps, due to a Jahn-Teller (J-T) effect [2]. Using energy-dependent soft x-ray microscopy [3,4] in this study we reveal and visualize the spatial distribution of the oxidation state of Mn, Fe and N at different electrode composition and after 50 cycles in a Li and in a Na battery. The high-resolution access to the metal L edge provided complementary details on the metal-ligand characteristic to the one already available by hard x-ray absorption, while the images demonstrate particles at different state of charge, likely caused by J-T-related passivations, in particular in the cycled lithiated samples. This confirms the superior stability to sodiation and provides an important support for strategies aimed to the suppression of fading.
- Published
- 2020