title: Structural, transport, and electrochemical investigation of novel AMSO4F (A = Na, Li; M = Fe, Co, Ni, Mn) metal fluorosulphates prepared using low temperature synthesis routes.
abstract: We have recently reported a promising 3.6 V metal fluorosulphate (LiFeSO(4)F) electrode, capable of high capacity, rate capability, and cycling stability. In the current work, we extend the fluorosulphate chemistry from lithium to sodium-based systems. In this venture, we have reported the synthesis and crystal structure of NaMSO(4)F candidates for the first time. As opposed to the triclinic-based LiMSO(4)F phases, the NaMSO(4)F phases adopt a monoclinic structure. We further report the degree and possibility of forming Na(Fe(1-x)M(x))SO(4)F and (Na(1-x)Li(x))MSO(4)F (M = Fe, Co, Ni) solid-solution phases for the first time. Relying on the underlying topochemical reaction, we have successfully synthesized the NaMSO(4)F, Na(Fe(1-x)M(x))SO(4)F, and (Na(1-x)Li(x))MSO(4)F products at a low temperature of 300 degrees C using both ionothermal and solid-state syntheses. The crystal structure, thermal stability, ionic conductivity, and reactivity of these new phases toward Li and Na have been investigated. Among them, NaFeSO(4)F is the only one to present some redox activity (Fe(2+)/Fe(3+)) toward Li at 3.6 V. Additionally, this phase shows a pressed-pellet ionic conductivity of 10(-7) S x cm(-1). These findings further illustrate the richness of the fluorosulphate crystal chemistry, which has just been recently unveiled.
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides, Université de Picardie Jules Verne, CNRS UMR 6007, 33 rue Saint Leu, 80039, Amiens, France.
authors.forename: Prabeer
authors.initials: P
authors.lastname: Barpanda
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Chotard
authors.forename: Nadir
authors.initials: N
authors.lastname: Recham
authors.forename: Charles
authors.initials: C
authors.lastname: Delacourt
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ati
authors.forename: Loic
authors.initials: L
authors.lastname: Dupont
authors.forename: Michel
authors.initials: M
authors.lastname: Armand
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Tarascon