Sango Co., Ltd.

City of Nagoya

Makoto Daifuku

Kouichi Izuhara

Yasushi Miyata

Shunsuke Ouchi

A negative electrode material for a lithium secondary battery, having one of iron foil and iron-base alloy foil, wherein the one of iron foil and iron-base alloy foil which has a surface profile having a plurality of concave shaped hollows formed by heat treating with laser beam irradiation and the surface is a surface which contacts with an electrolyte solution for a lithium secondary battery. There is further provided a lithium secondary battery including a negative electrode of the negative electrode material, a positive electrode using a lithium compound as an active material, an electrolyte between the negative electrode and the positive electrode, and a separator dividing the negative electrode and the positive electrode from each other.

Negative electrode material for lithium secondary battery and method for manufacturing the same

A negative electrode for a lithium-ion secondary cell is configured in a novel manner, having a charge-discharge capacity, as determined per unit weight of the carbon used in the electrode, that is markedly higher than the theoretical capacity of graphite, and having a surface that is stabilized against repeated charging and discharging. A negative electrode for a lithium-ion secondary cell in which a carbon layer obtained by building up and growing a graphene sheet is formed on the surface of a substrate comprising an iron-based metal, the carbon layer being formed in a diagonal direction in relation to the substrate, and the carbon layer being used as the surface of the negative electrode. As measured using an argon laser having a wavelength of 532 nm, the Raman spectrum of the graphite that constitutes the carbon nanochip layer has a g/d ratio of 0.30-0.80.

Negative electrode for lithium-ion secondary cell and method for manufacturing same

Provided is a negative electrode having a new structure for realizing a lithium secondary battery having increased charging/discharging capacities and a battery capacity that is reduced less due to repeated charging/discharging. The negative electrode for a lithium secondary battery includes a current collector substrate; a carbon nanochips layer including graphene sheets grown to incline in irregular directions independently from the current collector substrate; and a silicon thin film layer on the carbon nanochips layer, in which gaps among the carbon nanochips are formed between the silicon thin film layer and the current collector substrate. The Raman spectrum of graphite forming the carbon nanochips layer has a g/d ratio of 0.30 to 0.80, both inclusive, and the crystallinity level of the graphite is lower than that of graphite forming carbon nanowalls. The carbon nanochips layer can be formed by a plasma CVD method using a gaseous mixture of methane and hydrogen, for example.

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Nishikamo-gun, Japan

Makoto Daifuku