Positive electrode active material, non-aqueous electrolyte secondary battery and method for producing positive electrode active material
AssigneeSony Corporation
InventorsAtsuo Yamada, Guohua Li, Hideto Azuma
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Abstract
A non-aqueous electrolyte secondary battery employing a positive electrode active material containing a compound represented by the general formula LixMyPO4, where 0<x≦2 and 0.8≦y≦1.2, with M containing a 3d transition metal, where LixMyPO4 encompasses that with the grain size not larger than 10 μm. The non-aqueous electrolyte secondary battery has superior cyclic characteristics and a high capacity.
Claims15
A positive electrode active material containing a compound represented by the general formula LixMyPO4, where 0<x≦2 and 0.8≦y≦1.2, with M containing a 3d transition metal,
- where said LixMyPO4 encompasses that with the grain size not larger than 10 μm.
A positive electrode active material containing a compound represented by the general formula Lix(FeyM1−y)PO4, where 0.9≦x≦1.1 and 0<y≦1, with M containing a 3d transition metal,
- wherein, in a spectrum for said Lix(FeyM1−y)PO4 obtained by the Moessbauer spectroscopic method, A/B is less than 0.3, where A is the area strength of a spectrum obtained by the Moessbauer spectroscopic method of not less than 0.1 mm/sec and not larger than 0.7 mm/sec and B is the area strength of a spectrum obtained by the Moessbauer spectroscopic method not less than 0.8 mm/sec and not larger than 1.5 mm/sec.
A non-aqueous electrolyte secondary battery comprising a positive electrode having a positive electrode active material containing a compound represented by the general formula LixMyPO4, where 0<x≦2 and 0.8≦y≦1.2, with M containing a 3d transition metal, a negative electrode having a negative electrode active material, said positive electrode active material and the negative electrode active material being capable of reversibly doping/undoping lithium, and a non-aqueous electrolyte, wherein said LixMyPO4 encompasses that with the grain size not larger than 10 μm.
A non-aqueous electrolyte secondary battery comprising a positive electrode having a positive electrode active material containing a compound represented by the general formula Lix(FeyM1−y)PO4, where 0.9≦x≦1.1 and 0<y≦1, with M containing a 3d transition metal, a negative electrode having a negative electrode active material, said positive electrode active material and the negative electrode active material being capable of reversibly doping/undoping lithium, and a non-aqueous electrolyte,
- wherein, in a spectrum for said Lix(FeyM1−y)PO4 obtained by the Moessbauer spectroscopic method, A/B, A/B is less than 0.3, where A is the area strength of a spectrum obtained by the Moessbauer spectroscopic method not less than 0.1 mm/sec and not larger than 0.7 mm/sec and B is the area strength of a spectrum obtained by the Moessbauer spectroscopic method not less than 0.8 mm/sec and not larger than 1.5 mm/sec.
A method for producing a positive electrode active material comprising:
- a mixing step of mixing a starting materials for synthesis of a compound represented by the general formula LixMyPO4, where 0<x≦2 and 0.8≦y≦1.2, with M containing a 3d transition metal;
- and
- a sintering step of sintering and reacting said precursor obtained in said mixing step;
- wherein, in said sintering step, said precursor is sintered at a temperature not lower than 400° C. and not higher than 700° C.
Dependencies are inferred from the claim text.