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AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsTeruaki Ochiai, Takahiro Kawakami, Mayumi Mikami, Yohei Momma, Masahiro Takahashi, Ayae Tsuruta
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A positive electrode active material which can improve cycle characteristics of a secondary battery is provided. Two kinds of regions are provided in a superficial portion of a positive electrode active material such as lithium cobaltate which has a layered rock-salt crystal structure. The inner region is a non-stoichiometric compound containing a transition metal such as titanium, and the outer region is a compound of representative elements such as magnesium oxide. The two kinds of regions each have a rock-salt crystal structure. The inner layered rock-salt crystal structure and the two kinds of regions in the superficial portion are topotaxy; thus, a change of the crystal structure of the positive electrode active material generated by charging and discharging can be effectively suppressed. In addition, since the outer coating layer in contact with an electrolyte solution is the compound of representative elements which is chemically stable, the secondary battery having excellent cycle characteristics can be obtained.
A method of manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution, the positive electrode comprising a positive electrode active material, the method comprising the steps of:
A method of manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution, the positive electrode comprising a positive electrode active material, the method comprising the steps of:
A method of manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution, the positive electrode comprising a positive electrode active material, the method comprising the steps of:
A method of manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution, the positive electrode comprising a positive electrode active material, the method comprising the steps of:
Dependencies are inferred from the claim text.