Synthesis of (Li2Fe1- yMny)SO Antiperovskites with Comprehensive Investigations of (Li2Fe0.5Mn0.5)SO as Cathode in Li-ion Batteries

Mikhail V Gorbunov; Salvatore Carrocci; Sebastian Maletti; Martin Valldor; Thomas Doert; Silke Hampel; Ignacio Guillermo Gonzalez Martinez; Daria Mikhailova; Nico Gräßler

doi:10.1021/acs.inorgchem.0c01753

Synthesis of (Li₂Fe_{1- y}Mn_y)SO Antiperovskites with Comprehensive Investigations of (Li₂Fe_0.5Mn_0.5)SO as Cathode in Li-ion Batteries

Inorg Chem. 2020 Nov 2;59(21):15626-15635. doi: 10.1021/acs.inorgchem.0c01753. Epub 2020 Oct 13.

Authors

Mikhail V Gorbunov¹, Salvatore Carrocci¹, Sebastian Maletti¹, Martin Valldor^{1

2}, Thomas Doert³, Silke Hampel¹, Ignacio Guillermo Gonzalez Martinez¹, Daria Mikhailova¹, Nico Gräßler¹

Affiliations

¹ Leibniz Institute for Solid State and Materials Research (IFW) Dresden e.V., Helmholtzstrasse 20, D-01069 Dresden, Germany.
² Department of Chemistry, University of Oslo, Postbox 1033, Blindern, N - 0315 Oslo, Norway.
³ Faculty of Chemistry and Food Chemistry, Technische Universität Dresden 01069 Dresden, Germany.

PMID: 33047957
DOI: 10.1021/acs.inorgchem.0c01753

Abstract

A series of solid solutions (Li₂Fe_1-yMn_y)SO with a cubic antiperovskite structure was successfully synthesized. The composition (Li₂Fe_0.5Mn_0.5)SO was intensively studied as a cathode in Li-ion batteries showing a reversible specific capacity of 120 mA h g^-1 and almost a 100% Coulombic efficiency after 50 cycles at 0.1C meaning extraction/insertion of 1 Li per formula unit during 10 h. Operando X-ray absorption spectroscopy confirmed the redox activity of both Fe²⁺ and Mn²⁺ cations during battery charge and discharge, while operando synchrotron X-ray diffraction studies revealed a reversible formation of a second isostructural phase upon Li-removal and insertion at least for the first several cycles. In comparison to (Li₂Fe)SO, the presence of Mn stabilizes the crystal structure of (Li₂Fe_0.5Mn_0.5)SO during battery operation, although post mortem TEM studies confirmed a gradual amorphization after 50 cycles. A lower specific capacity of (Li₂Fe_0.5Mn_0.5)SO in comparison to (Li₂Fe)SO is probably caused by slower kinetics, especially in the two-phase region, as confirmed by Li-diffusion coefficient measurements.