title: Synthesis, Structure, and Electrochemical Properties of K-Based Sulfates K2M2(SO4)3with M = Fe and Cu.
abstract: Stabilizing new host structures through potassium extraction from K-based polyanionic materials has been proven to be an interesting approach to develop new Li+/Na+insertion materials. Pursuing the same trend, we here report the feasibility of preparing langbeinite "Fe2(SO4)3" via electrochemical and chemical oxidation of K2Fe2(SO4)3. Additionally, we succeeded in stabilizing a new K2Cu2(SO4)3phase via a solid-state synthesis approach. This novel compound crystallizes in a complex orthorhombic structure that differs from that of langbeinite as deduced from synchrotron X-ray and neutron powder diffraction. Electrochemically, the performance of this new phase is limited, which we explain in terms of sluggish diffusion kinetics. We further show that K2Cu2(SO4)3decomposes into K2Cu3O(SO4)3on heating, and we report for the first time the synthesis of fedotovite K2Cu3O(SO4)3. Finally, the fundamental attractiveness of these S =1/2systems for physicists is examined by neutron magnetic diffraction, which reveals the absence of a long-range ordering of Cu2+magnetic moments down to 1.5 K.
authors.affiliation: UMR 8260 "Chimie du Solide et Energie", Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.|Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 , 80039 Amiens Cedex, France.|Sorbonne Universités-UPMC Univ Paris 06 , 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Laura
authors.identifier: http://orcid.org/0000-0001-8128-126X
authors.initials: L
authors.lastname: Lander
authors.affiliation: UMR 8260 "Chimie du Solide et Energie", Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.|Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 , 80039 Amiens Cedex, France.|Sorbonne Universités-UPMC Univ Paris 06 , 4 Place Jussieu, F-75005 Paris, France.|Institut Universitaire de France , 1 rue Descartes, 75231 Paris Cedex 05, France.
authors.forename: Gwenaëlle
authors.initials: G
authors.lastname: Rousse
authors.affiliation: UMR 8260 "Chimie du Solide et Energie", Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.|EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Dmitry
authors.identifier: http://orcid.org/0000-0002-6384-6690
authors.initials: D
authors.lastname: Batuk
authors.affiliation: Institut Néel CNRS, Université Grenoble Alpes , 38042 Grenoble, France.|CNRS, Institut Néel , F-38000 Grenoble, France.
authors.forename: Claire V
authors.initials: CV
authors.lastname: Colin
authors.affiliation: UMR 8260 "Chimie du Solide et Energie", Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Daniel Alves
authors.initials: DA
authors.lastname: Dalla Corte
authors.affiliation: UMR 8260 "Chimie du Solide et Energie", Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.|Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 , 80039 Amiens Cedex, France.|Sorbonne Universités-UPMC Univ Paris 06 , 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Tarascon