title: Insights into the Impact of Impurities and Non-Stoichiometric Effects on the Electrochemical Performance of Li2MnSiO4.
abstract: A series of Li2MnSiO4samples with various Li, Mn, and/or Si concentrations are reported to study for the first time the effect of impurities and deviation from ideal stoichiometry on electrochemical behavior. Carbon-coated and nanosized powders are obtained at 600 °C and compared with those synthetized at 900 °C. Samples are investigated using XRD, SEM, high-resolution TEM, attenuated total reflection infrared spectroscopy and Brunauer-Emmett-Teller surface area to characterize crystal structure, particle size, impurity amount, morphology, and surface area. Electrochemical performance depends on impurities such as MnO as well as crystallite size, surface area, and non-stoichiometric phases, which lead to the formation of additional polymorphs such as Pmnb and P21/n of Li2MnSiO4at low calcination temperatures. A systematic analysis of the main parameters affecting the electrochemical behavior is performed and trends in synthesis are identified. The findings can be applied to optimize different synthesis routes for attaining stoichiometric and phase-pure Pmn21Li2MnSiO4as cathode material for Li-ion batteries.
authors.affiliation: Accumulators Materials Research (ECM), Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Helmholtzstr. 8, 89081, Ulm, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Fleischmann
authors.affiliation: Accumulators Materials Research (ECM), Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Helmholtzstr. 8, 89081, Ulm, Germany. marilena.mancini@zsw-bw.de.
authors.forename: M
authors.identifier: http://orcid.org/0000-0001-9088-6068
authors.initials: M
authors.lastname: Mancini
authors.affiliation: Accumulators Materials Research (ECM), Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Helmholtzstr. 8, 89081, Ulm, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Axmann
authors.affiliation: Electron Microscopy Group of Materials Science, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Golla-Schindler
authors.affiliation: Electron Microscopy Group of Materials Science, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Kaiser
authors.affiliation: Accumulators Materials Research (ECM), Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Helmholtzstr. 8, 89081, Ulm, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Wohlfahrt-Mehrens
mesh_terms: D004563:Electrochemistry; D018020:Lithium Compounds / Q000737:chemistry*; D008854:Microscopy, Electron; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D018020:Lithium Compounds
keywords: electrochemistry; energy conversion; lithium; manganese; silicates