title: Enhancing the Lithium Ion Conductivity in Lithium Superionic Conductor (LISICON) Solid Electrolytes through a Mixed Polyanion Effect.
abstract: Lithium superionic conductor (LISICON)-related compositions Li4±xSi1-xXxO4(X = P, Al, or Ge) are important materials that have been identified as potential solid electrolytes for all solid state batteries. Here, we show that the room temperature lithium ion conductivity can be improved by several orders of magnitude through substitution on Si sites. We apply a combined computer simulation and experimental approach to a wide range of compositions (Li4SiO4, Li3.75Si0.75P0.25O4, Li4.25Si0.75Al0.25O4, Li4Al0.33Si0.33P0.33O4, and Li4Al1/3Si1/6Ge1/6P1/3O4) which include new doped materials. Depending on the temperature, three different Li+ion diffusion mechanisms are observed. The polyanion mixing introduced by substitution lowers the temperature at which the transition to a superionic state with high Li+ion conductivity occurs. These insights help to rationalize the mechanism of the lithium ion conductivity enhancement and provide strategies for designing materials with promising transport properties.
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides (UMR CNRS 7314), Université de Picardie Jules Verne , 33 rue Saint Leu, 80039 Amiens Cedex, France.|Department of Chemistry, University of Bath , Bath BA2 7AY, United Kingdom.|ALISTORE European Research Institute, FR CNRS 3104 , 80039 Amiens Cedex, France.|Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459 , 80039 Amiens, France.
authors.forename: Yue
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Chemistry, University of Bath , Bath BA2 7AY, United Kingdom.|ALISTORE European Research Institute, FR CNRS 3104 , 80039 Amiens Cedex, France.
authors.forename: Christopher
authors.identifier: http://orcid.org/0000-0002-5548-2655
authors.initials: C
authors.lastname: Eames
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides (UMR CNRS 7314), Université de Picardie Jules Verne , 33 rue Saint Leu, 80039 Amiens Cedex, France.|Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459 , 80039 Amiens, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Fleutot
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides (UMR CNRS 7314), Université de Picardie Jules Verne , 33 rue Saint Leu, 80039 Amiens Cedex, France.|Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459 , 80039 Amiens, France.
authors.forename: Rénald
authors.initials: R
authors.lastname: David
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides (UMR CNRS 7314), Université de Picardie Jules Verne , 33 rue Saint Leu, 80039 Amiens Cedex, France.|Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459 , 80039 Amiens, France.
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Chotard
authors.affiliation: Institut Laue-Langevin , 71 Avenue des Martyrs, F-38000 Grenoble, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Suard
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides (UMR CNRS 7314), Université de Picardie Jules Verne , 33 rue Saint Leu, 80039 Amiens Cedex, France.|ALISTORE European Research Institute, FR CNRS 3104 , 80039 Amiens Cedex, France.|Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459 , 80039 Amiens, France.
authors.forename: Christian
authors.identifier: http://orcid.org/0000-0001-7289-1015
authors.initials: C
authors.lastname: Masquelier
authors.affiliation: Department of Chemistry, University of Bath , Bath BA2 7AY, United Kingdom.|ALISTORE European Research Institute, FR CNRS 3104 , 80039 Amiens Cedex, France.
authors.forename: M Saiful
authors.initials: MS
authors.lastname: Islam
keywords: LISICON; diffusion mechanism; energy storage; mixed polyanion effect; solid electrolyte