A negative electrode for a lithium ion secondary battery includes: a negative electrode current collector (11); and a negative electrode active material for a lithium ion secondary battery, which is disposed on the negative electrode current collector and contains a carbon material and an aqueous binder. The carbon material is a graphite particle having a covering layer containing amorphous carbon by 5 wt % or less relative to a total weight of the carbon material.

Provided is a negative electrode for a lithium ion secondary battery including: a negative electrode current collector; and a negative electrode active material for a lithium ion secondary battery which is disposed on the negative electrode current collector and contains a carbon material and an aqueous binder. The carbon material is a graphite particle having a covering layer containing amorphous carbon by 5 wt % or less relative to a total weight of the carbon material

A method of increasing secondary power source capacity includes doping a compound into an electrolyte as an additive which binding energy is higher than binding energy of combinations that are formed at a secondary power source discharge, the compound being ZnKr or CdAr. The method can be used in manufacturing secondary power sources such as batteries for electrical machines, transport vehicles, and cars, and for power sources for portable and mobile electronic devices.

An apparatus for manufacturing a lithium-ion secondary cell negative-electrode carbon material by heat-treating carbon particles while causing the carbon particles to flow within a heat-treatment furnace, the apparatus having a heat-treatment furnace provided with a carbon-particle supply opening for supplying the carbon particles into the interior, and a negative-electrode carbon material recovery opening for taking out the negative-electrode carbon material from the interior and a cooling tank connected in an airtight manner to the negative-electrode carbon material recovery opening of the heat-treatment furnace, and provided with a cooling means.

An apparatus for manufacturing a lithium-ion secondary cell negative-electrode carbon material by heat-treating carbon particles while causing the carbon particles to flow within a heat-treatment furnace, the apparatus having a heat-treatment furnace provided with a carbon-particle supply opening for supplying the carbon particles into the interior, and a negative-electrode carbon material recovery opening for taking out the negative-electrode carbon material from the interior and a cooling tank connected in an airtight manner to the negative-electrode carbon material recovery opening of the heat-treatment furnace, and provided with a cooling means.

A secondary battery in which heat resistance is excellent and the formation of lithium dendrite is suppressed is provided. The present invention relates to a secondary battery comprising an electrode element comprising a positive electrode, a negative electrode and a separator, wherein the negative electrode comprises a carbon material (a) capable of absorbing and desorbing lithium ions and an oxide (b) capable of absorbing and desorbing lithium ions, and the separator comprises 50% by mass or more of a non-woven fabric having a thermal melting or thermal decomposition temperature of 160° C. or more.

A secondary battery in which heat resistance is excellent and the formation of lithium dendrite is suppressed is provided. The present invention relates to a secondary battery comprising an electrode element comprising a positive electrode, a negative electrode and a separator, wherein the negative electrode comprises a carbon material (a) capable of absorbing and desorbing lithium ions and an oxide (b) capable of absorbing and desorbing lithium ions, and the separator comprises 50% by mass or more of a non-woven fabric having a thermal melting or thermal decomposition temperature of 160° C. or more.

A method for charging a lithium ion secondary battery of the present invention includes a first step and a second step. In the first step, A, B, and C satisfy the relationship A>B and B<C, where A represents an average charging current value in the range where a charge rate of the lithium ion secondary battery is 0% or more and less than 40%, B represents an average charging current value in the range where the charge rate is 40% or more and 60% or less, and C represents an average charging current value in the range where the charge rate is more than 60%. In the first step, the ratio of C.sub.MAX to C.sub.MIN (C.sub.MAX/C.sub.MIN) is 1.01 to 3.00, where C.sub.MAX represents the maximum value of the charging current value and C.sub.MIN represents the minimum value of the charging current value.

Provided is a carbon material capable of obtaining a non-aqueous secondary battery, which has high capacity, initial efficiency, and low charging resistance and is excellent in productivity. As a result thereof, a high-performance non-aqueous secondary battery is stably provided with efficiency. A composite carbon material for a non-aqueous secondary battery is provided, which contains at least a bulk mesophase artificial graphite particle (A) and graphite particle (B) having an aspect ratio of 5 or greater, and which is capable of absorbing and releasing lithium ions. A graphite crystal layered structure of the graphite particle (B) is arranged in the same direction as a direction of an outer peripheral surface of the bulk mesophase artificial graphite particle (A) at a part of a surface of the bulk mesophase artificial graphite particle (A), and an average circularity of the composite carbon material is 0.9 or greater.

Provided is a carbon material capable of obtaining a non-aqueous secondary battery, which has high capacity, initial efficiency, and low charging resistance and is excellent in productivity. As a result thereof, a high-performance non-aqueous secondary battery is stably provided with efficiency. A composite carbon material for a non-aqueous secondary battery is provided, which contains at least a bulk mesophase artificial graphite particle (A) and graphite particle (B) having an aspect ratio of 5 or greater, and which is capable of absorbing and releasing lithium ions. A graphite crystal layered structure of the graphite particle (B) is arranged in the same direction as a direction of an outer peripheral surface of the bulk mesophase artificial graphite particle (A) at a part of a surface of the bulk mesophase artificial graphite particle (A), and an average circularity of the composite carbon material is 0.9 or greater.