Anode active material, manufacturing method thereof, and non-aqueous electrolyte secondary battery
AssigneesPanasonic Corporation, Osaka City University
InventorsTsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama, Hizuru Koshina
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Abstract
In order to provide a 3V level non-aqueous electrolyte secondary battery with a flat voltage and excellent cycle life at a high rate with low cost, the present invention provides a positive electrode represented by the formula: Li2±α[Me]4O8−x, wherein 0≦α<0.4, 0≦x<2, and Me is a transition metal containing Mn and at least one selected from the group consisting of Ni, Cr, Fe, Co and Cu, said active material exhibiting topotactic two-phase reactions during charge and discharge.
Claims24
A positive electrode active material represented by the composition formula:
- Li2±α[Me]4O8−x, wherein 0≦α<0.4, 0≦x<2, and Me is a transition metal containing Mn and at least one selected from the group consisting of Ni, Cr, Fe, Co and Cu, said active material exhibiting first and second topotactic two-phase reactions respectively during first and second stages of charge and discharge, and characterized in that the phase of the transition metal has a 2×2 superlattice.
A method for producing a positive electrode active material comprising:
- (1) a step of synthesizing a eutectic compound containing a Mn compound and at least one selected from the group consisting of Ni, Cr, Fe, Co and Cu;
- (2) a step of mixing said eutectic compound with a lithium compound;
- and
- (3) a step of subjecting the mixed compounds obtained by said step (2) to a first baking at a temperature of not less than 600° C.,
- whereby a positive electrode active material represented by the formula:
- Li2±α[Me]4O8−x, where 0≦α<0.4, 0≦x<2, and Me is a transition metal containing Mn and at least one selected from the group consisting of Ni, Cr, Fe, Co and Cu, said active material exhibiting first and second topotactic two-phase reactions respectively during first and second stages of charge and discharge is obtained.
Dependencies are inferred from the claim text.