NOVELTY - The lithium-ion secondary battery comprises a cathode, an anode, and an electrolytic solution. The anode includes an anode active material layer including anode active material particles, which include a core section and a coating section applied to a part or a whole of a surface of the core section. The core section includes a silicon-based material such as silicon oxide or a simple substance of silicon, and the coating section includes an amorphous or low-crystalline silicon-based material such as silicon oxide. The amorphous silicon-based material includes an amorphous region.    USE - The lithium-ion secondary battery is useful as a power supply for activating a power tool and an electric vehicle, as a power storage source for an energy storage system (all claimed) such as household battery systems storing power in case of emergency, and for portable electronic devices such as video cameras, digital still cameras, cellular phones, notebook personal computers, cordless telephones, headphone stereos, portable radios, portable televisions and personal digital assistants, portable home appliances such as electric shavers, memory devices such as backup power supplies and memory cards and medical electronic devices such as pacemakers and hearing aids, where the power tool includes electric drill and electric saw and the electric vehicle includes hybrid vehicle.    ADVANTAGE - The lithium-ion secondary battery has improved cycle characteristics, initial charge-discharge characteristics, storage characteristics, load characteristics and lifespan, and high energy density, capacity and safety performance.    DETAILED DESCRIPTION - The lithium-ion secondary battery comprises a cathode, an anode, and an electrolytic solution. The anode includes an anode active material layer including anode active material particles, which include a core section and a coating section applied to a part or a whole of a surface of the core section. The core section includes a silicon-based material such as silicon oxide (SiOx), where x is 0-0.5 or a simple substance of silicon, and the coating section includes an amorphous or low-crystalline silicon-based material such as silicon oxide (SiOy), where y is 0.5-1.8. The amorphous silicon-based material includes an amorphous region, and the low-crystalline silicon-based material includes an amorphous region and crystalline regions (crystal grains). An average area proportion of the crystal grains corresponding to (111) plane and (220) plane of silicon is less than or equal to 35%, and an average particle diameters of the crystal grains corresponding to (111) plane and (220) plane of silicon is less than or equal to 55 nm. The average area proportion and the average particle diameter of the crystal grains in an inner part are equal to or larger than the proportion and diameter in an outer part. The crystal grains are dotted in the amorphous region. The coating section is configured of layers. In the core section, a half-width (2 theta ) of a diffraction peak corresponding to (111) crystal plane of silicon obtained by X-ray diffraction is greater than or equal to 0.6 degrees , and a crystallite size corresponding to the (111) crystal plane is less than or equal to 90 nm. A median diameter of the core section is 0.5-20 mu m, and an average thickness and an average coverage of the coating section are 1-5000 nm and greater than or equal to 30% respectively. The anode active material layer is disposed on an anode current collector, and further includes a carbon material. A content of silicon in the core section is 20-80 atomic%. A bonding state (valence number) of silicon atoms to oxygen atoms in the amorphous silicon-based material included in the coating section is a mixed state of zerovalence (Si0+), monovalence (Si1+), divalence (Si2+), trivalence (Si3+) and tetravalence (Si4+). An abundance ratio (atomic ratio) of the bonding state of silicon atoms satisfies a relationship of Si0+ less than or equal to Si1++Si2++Si3++Si4+ and relationships of Si1+ less than or equal to Si3+, Si2+ less than or equal to Si3+, Si1+ less than or equal to Si4+ and Si2+ less than or equal to Si4+, where the abundance ratio of Si4+ is greater than or equal to 30 atomic%. The anode active material particles include an additional coating film that is applied to a part or a whole of a surface of the coating section and has lower electrical resistance than the core section and the coating section. An INDEPENDENT CLAIM is included for an anode for lithium-ion secondary battery.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic sectional view of a prismatic type secondary battery.    Battery can (11)    Insulating plate (12)    Battery cover (13)    Terminal plate (14)    Cathode pin. (15)