Structural and electrochemical characterizations of P2 and new O3-NaxMn1-yFeyO2 phases prepared by auto-combustion synthesis for Na-ion batteries

Benoît Mortemard de Boisse (1) , Dany Carlier-Larregaray (1) , Marie Guignard (1) , Claude Delmas (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Using auto-combustion synthesis route followed by a 1000°C heat-treatment, we succeeded to prepare four Nax(Mn,Fe)O2 phases: P2-Na0.67Mn2/3Fe1/3O2, P2-Na0.71Mn1/2Fe1/2O2, and new Na-deficient O3-Na0.82Mn1/3Fe2/3O2 and O3-Na∼0.8Mn1/2Fe1/2O2 phases. We studied their structures by X-ray Diffraction and their electrochemical properties as positive electrode in Na-cells that were reversibly charged and discharged in the 1.5 and 3.8 V range vs. Na+/Na, leading to discharge capacities between 135 and 155 mAh.g−1. The shapes of the cycling curves are discussed together with the stacking of the phases and the redox processes involved in the Na intercalation/deintercalation reaction. In some cases the Fe(IV) state is clearly reached.

Mots clés: Batteries; Solid solution; Electrochemistry

Domaines: Matériaux

Benoît Mortemard de Boisse, Dany Carlier-Larregaray, Marie Guignard, Claude Delmas. Structural and electrochemical characterizations of P2 and new O3-NaxMn1-yFeyO2 phases prepared by auto-combustion synthesis for Na-ion batteries. Journal of The Electrochemical Society, 2013, 160 (4), pp.A569-A574. ⟨10.1149/2.032304jes⟩. ⟨hal-00816913⟩