Insights into the Impact of Impurities and Non‐Stoichiometric Effects on the Electrochemical Performance of Li2MnSiO4. Issue 20 (6th October 2016)

• Record Type: Journal Article
• Authors: Fleischmann, S.; Mancini, M.; Axmann, P.; Golla‐Schindler, U.; Kaiser, U.; Wohlfahrt‐Mehrens, M.
• Is Part Of: ChemSusChem. Volume 9:Issue 20(2016:Oct.)
• Page Start: 2982
• Page End: 2993
• Publication Date: 2016-10-06
• Subjects: electrochemistry -- energy conversion -- lithium -- manganese -- silicates; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201600894
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: A series of Li2 MnSiO4 samples 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 P 21 / n of Li2 MnSiO4 at 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 Pmn 21 Li2 MnSiO4 as cathode material for Li‐ion batteries. Abstract : Polymorphs to be avoided? A series of Li2 MnSiO4 samples with different Li, Mn, and/or Si concentrations are reported to study the effect of impurities and deviation from ideal stoichiometry on electrochemical behavior. Impurities such as MnO and non‐stoichiometric phases leading to the formation of additional polymorphs such as Pmnb and P 21 / n of Li2 MnSiO4 at low calcination temperatures drastically reduce the electrochemical performance.