Synthesis and investigations on an O4-LiCoO₂ polytype

Romain Berthelot (1) , Dany Carlier-Larregaray (1) , Michaël Pollet (1) , Jean-Pierre Doumerc (1) , Claude Delmas (1)

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

A polytype of LiCoO₂ has been synthesized through an ion-exchange reaction. By exchanging Na⁺ for Li⁺ ions from an OP4-(Li/Na)CoO₂-mixed cobaltite, a LiCoO₂ stacking is obtained. It alternatively combines O2- and O3-LiCoO₂ polytypes and corresponds to an O4 stacking. The phase crystallizes in the hexagonal system with cell parameters a_hex = 2.802(1) Å and c_hex = 18.89(2) Å. As the O2 phase, the O4-LiCoO₂, is metastable; it transforms into the thermodynamically stable O3-LiCoO₂at around 350–400°C. The crystallographic data, the thermal properties, and the electrochemical behavior of this phase are presented.

Domaines: Matériaux

Romain Berthelot, Dany Carlier-Larregaray, Michaël Pollet, Jean-Pierre Doumerc, Claude Delmas. Synthesis and investigations on an O4-LiCoO₂ polytype. Electrochemical and Solid-State Letters, 2009, 12 (11), pp.A207-A210. ⟨10.1149/1.3204643⟩. ⟨hal-00432961⟩