Marinite Li₂M(SO₄)₂ (M = Co, Fe, Mn) and Li₁Fe(SO₄)₂: Model Compounds for Super-Super-Exchange Magnetic Interactions

Abstract

New materials initially designed for battery electrodes are often of interest for magnetic study, because their chemical compositions include 3d transition metals. We report here on the magnetic properties of marinite phases Li2M(SO4)2 (M = Fe, Co, Mn) and Li1Fe(SO4)2, which all order antiferromagnetically at low temperature. From neutron powder diffraction, we propose a model for their ground-state magnetic structures. The magnetism of marinite Li2M(SO4)2 compounds unambiguously results from super-super-exchange interactions; therefore, these materials can be considered as a model case for which the Goodenough-Kanamori-Anderson rules can be tested.

Polyanion Compounds as Cathode Materials for Li-Ion Batteries

“…Conversely, each SO 4 group is only bound to three MO 6 octahedra, with the fourth corner of the non-shared tetrahedron pointing to an open channel where lithium ions reside. Later, in 2013, Reynaud et al [102] reported that Li 2 Mn(SO 4 ) 2 crystallized into the same structure as the iron and cobalt compounds, which was confirmed by Rietveld refinement of the XRD data.…”

“…First, stoichiometric amounts of Li 2 SO 4 and MSO 4 were thoroughly mixed using a Spex Miller 8000M, with the resulting powder next pressed into a pellet. Finally, the pellet is annealed at 325°C for 12-48 h, either under air (M = Co, Mn) or in a quartz tube sealed under vacuum (M = Fe) [102].…”

“…Li 2 M(SO 4 ) 2 (M = Fe, Co) has been fully indexed to the monoclinic unit cell with the space group P2 1 /c [98,102]. The structure, as shown in Fig.…”

“…Moreover, magnetic properties of the marinite phases of Li 2 M(SO 4 ) 2 (M = Fe, Co, Mn) and Li 1 Fe(SO 4 ) 2 were proposed in order to aid the investigation of their magnetic structures [102]. In 2013, Reynaud et al [102] reported on the temperature-dependent magnetic susceptibilities of the four marinite compounds and used low-temperature neutron powder diffraction to determine their magnetic structures.…”

“…In 2013, Reynaud et al [102] reported on the temperature-dependent magnetic susceptibilities of the four marinite compounds and used low-temperature neutron powder diffraction to determine their magnetic structures. The Li 1 Fe(SO 4 ) 2 was prepared by chemical delithiation from Li 2 Fe (SO 4 ) 2 .…”