Irreversible Structural Changes of Copper Hexacyanoferrate Used as a Cathode in Zn‐Ion Batteries. Issue 22 (25th February 2020)

• Record Type: Journal Article
• Authors: Lim, Joohyun; Kasiri, Ghoncheh; Sahu, Rajib; Schweinar, Kevin; Hengge, Katharina; Raabe, Dierk; La Mantia, Fabio; Scheu, Christina
• Is Part Of: Chemistry. Volume 26:Issue 22(2020)
• Page Start: 4917
• Page End: 4922
• Publication Date: 2020-02-25
• Subjects: copper hexacyanoferrate -- degradation -- electron energy loss spectroscopy -- electron microscopy -- energy conversion; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201905384
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The structural changes of copper hexacyanoferrate (CuHCF), a Prussian blue analogue, which occur when used as a cathode in an aqueous Zn‐ion battery, are investigated using electron microscopy techniques. The evolution of Zn x Cu1− x HCF phases possessing wire and cubic morphologies from initial CuHCF nanoparticles are monitored after hundreds of cycles. Irreversible introduction of Zn ions to CuHCF is revealed locally using scanning transmission electron microscopy. A substitution mechanism is proposed to explain the increasing Zn content within the cathode material while simultaneously the Cu content is lowered during Zn‐ion battery cycling. The present study demonstrates that the irreversible introduction of Zn ions is responsible for the decreasing Zn ion capacity of the CuHCF cathode in high electrolyte concentration. Abstract : The morphology, composition, oxidation state, and crystal structure changes occurring in copper hexacyanoferrate‐based cathodes in aqueous Zn‐ion batteries are investigated to understand degradation of the cathodes after few hundred cycles. Electron microscopy reveals the substitution of Cu ions by Zn ions in the lattice resulting in the formation of wires and cubes from the initial copper hexacyanoferrate nanoparticles.