Structure of Li₂MnO₃ with different degrees of defects

Adrien Boulineau (1) , Laurence Croguennec (1) , Claude Delmas (1) , François Weill (1, 2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 CREMEN - Centre de Ressources en Microscopie Electronique et Microanalyse

The synthesis and structural properties of the layered oxide Li₂MnO₃ have been studied in details. It represents a key for a better understanding of the complex structural evolutions pointed out in the materials like Li(Li,Ni,Mn,Co)O₂ when they are used as positive electrode materials in lithium-ion batteries. Li₂MnO₃ samples were prepared either via coprecipitation or via a two step solid state reaction followed by different annealing treatments. Using X-ray and electron diffraction in combination with diffraction data simulations, we show that in function of the synthesis conditions, Li₂MnO₃ is obtained with various degrees of disorder, along the c monoclinic direction, in the stacking of the ordered Li_1/3Mn_2/3 sheets within the cfc oxygen packing. We show that this disorder decreases when the synthesis temperature increases but the synthesis of a material free of stacking faults is not possible with these synthesis routes. Finally, the similarities between the evolutions pointed out in Li₂MnO₃ due to the synthesis conditions and those previously observed in the materials like Li(Li,Ni,Mn,Co)O₂ related to the evolution of the cations distribution in the slabs are underlined.

Mots clés: Li₂MnO₃; Layered oxides; X-ray diffraction; Electron diffraction; Defects; Stacking faults

Domaines: Matériaux

Adrien Boulineau, Laurence Croguennec, Claude Delmas, François Weill. Structure of Li₂MnO₃ with different degrees of defects. Solid State Ionics, 2010, 180 (40), pp.1652-1659. ⟨10.1016/j.ssi.2009.10.020⟩. ⟨hal-00463590⟩