Search for new manganese-cobalt oxides as positive electrode materials for lithium batteries

Pierre Strobel (1) , Jérémy Tillier , Audrey Diaz , Alejandro Ibarra-Palos , François Thiéry , Jean-Bruno Soupart (2)

1 NEEL - MRS - Matériaux, Rayonnements, Structure
2 R & D Department

Two new mixed manganese-cobalt oxides for lithium battery positive electrode materials were obtained using original synthesis routes. Compound I, "LMCO" is a new form of LiMnCoO4 obtained by ion-exchange from NaMnCoO4. Compound II, "MCO" is a nanometric material with formula Mn1-x CoxO≈2 obtained by quenching in specific conditions. We showed recently that the electro-chemical properties of this materials were dramatically enhanced by cobalt doping [Strobel et al., J. Mater. Chem. 15 (2005) 4799]. The effect of cobalt content on its electrochemical behaviour is reported in detail here. Compound I gives rise to two reversible single-phase intercalation reactions centered at 2.7 and 4.4 V on discharge, corresponding to Co3+/Co4+ and Mn3+/Mn4+ redox couples, respectively. The initial capacity is 160 mAh/g at low regime, but stabilizes at ca.100 mAh/g on extended cycling. Compound II gives a single plateau with a much higher capacity. An optimum ratio of Co:Mn = 0.20 was found and gives a capacity of 175 mAh/g after 60 cycles in the potential window 2.0-4.2 V.

Domaines: Chimie inorganique; Matériaux

Pierre Strobel, Jérémy Tillier, Audrey Diaz, Alejandro Ibarra-Palos, François Thiéry, et al.. Search for new manganese-cobalt oxides as positive electrode materials for lithium batteries. Journal of Power Sources, 2007, 174 (2), pp.910-915. ⟨10.1016/j.jpowsour.2007.06.080⟩. ⟨hal-00186061⟩