A negative active material for a rechargeable lithium battery includes a carbon-based active material including highly crystalline natural graphite and artificial graphite. The carbon-based active material has a peak intensity ratio (P2/P4) of about 0.3 to about 0.4, wherein P2 refers to the 101 peak of a rhombohedral crystal grain and P4 refers to the 101 peak of a hexagonal crystal grain, as measured by X-ray diffraction.

The present invention provides a binder for a secondary battery that can reduce the initial resistance value of the secondary battery. A binder for a secondary battery comprising a polymer compound, wherein the polymer compound contains repeating units represented by formulae (1), (2), and (3):

##STR00001## in formula (1), R.sup.1 is a hydrogen atom or a methyl group, and M is a hydrogen atom or an alkali metal atom; and in formula (3), R.sup.2 is a hydrogen atom or a methyl group; and when a total ratio of repeating units constituting the polymer compound is taken as 100 mol %, a total ratio of the repeating unit represented by formula (3) is less than 2 mol %.

The present invention provides a binder for a secondary battery that can reduce the initial resistance value of the secondary battery. A binder for a secondary battery comprising a polymer compound, wherein the polymer compound contains repeating units represented by formulae (1), (2), and (3):

##STR00001## in formula (1), R.sup.1 is a hydrogen atom or a methyl group, and M is a hydrogen atom or an alkali metal atom; and in formula (3), R.sup.2 is a hydrogen atom or a methyl group; and when a total ratio of repeating units constituting the polymer compound is taken as 100 mol %, a total ratio of the repeating unit represented by formula (3) is less than 2 mol %.

According to the present disclosure, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, so as to contribute in improving the safety property of the secondary battery. The manufacturing method of the electrode plate herein disclosed includes a precursor preparing step for preparing an electrode precursor 20A including an active material provided area A1 in which an electrode active material layer 24 is provided on a surface of the electrode core 22 and including a core exposed area A2 in which the electrode active material layer 24 is not provided and the electrode core 22 is exposed, and an active material provided area cutting step for cutting the active material provided area A1 by a pulse laser, and a core exposed area cutting step for cutting the core exposed area A2 by the pulse laser. Then, in the case where the pulse width (ns) of the pulse laser is represented by X and the lap rate (%) is represented by Y for the core exposed area cutting step, a condition represented by Y≥−3log X+106 is satisfied. According to the manufacturing method of the electrode plate as described above, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, and thus it is possible to contribute in improving the safety property of the secondary battery.

The present invention discloses a method for making lead-carbon electrode sheets, lead-carbon electrode sheets and lead-carbon battery. The method consists of steps of oxidizing lead under low-temperature atmosphere and the oxidized lead is used as interface layer of lead-carbon coupling, and using a specialized ventilation method for the carbon to coat the lead. The interface layer of oxidized lead forms a stable interface between the carbon and the lead. Meanwhile, through controlling pressure and temperature, a multi-porous metal composite is formed and the porosity can be penetration paths for air and liquid when the multi-porous metal composite is applied. The lead-carbon composite is applied as a lead-carbon electrode sheet and is further welded as a lead-carbon electrode sheet of a lead-carbon battery. The lead-carbon battery carrying the lead-carbon electrode demonstrates Coulomb efficiency of 100% without heat loss on an unsaturated charge-discharge condition of high-efficiency charging and high-efficiency discharging.

The present invention discloses a method for making lead-carbon electrode sheets, lead-carbon electrode sheets and lead-carbon battery. The method consists of steps of oxidizing lead under low-temperature atmosphere and the oxidized lead is used as interface layer of lead-carbon coupling, and using a specialized ventilation method for the carbon to coat the lead. The interface layer of oxidized lead forms a stable interface between the carbon and the lead. Meanwhile, through controlling pressure and temperature, a multi-porous metal composite is formed and the porosity can be penetration paths for air and liquid when the multi-porous metal composite is applied. The lead-carbon composite is applied as a lead-carbon electrode sheet and is further welded as a lead-carbon electrode sheet of a lead-carbon battery. The lead-carbon battery carrying the lead-carbon electrode demonstrates Coulomb efficiency of 100% without heat loss on an unsaturated charge-discharge condition of high-efficiency charging and high-efficiency discharging.

A production method is provided in which submicronic particles containing silicon are incorporated into a matrix, wherein, during the incorporation of the particles, the particles are in a compacted state with a bulk density of more than 0.10 grams per cubic centimeter, and the compacted particles have a specific surface area at least 70% of that of the particles considered separately without contact between each other.

A nonaqueous electrolyte secondary battery using a silicon compound as a negative electrode active material, suppress deformation of a negative electrode. An embodiment includes a winding type electrode body in which a positive electrode and a negative electrode are spirally wound with at least one separator interposed therebetween. In a negative electrode mixture layer, a silicon compound is contained as a negative electrode active material. A winding-start side end of the negative electrode mixture layer extends to a winding-start end side of the electrode body past a winding-start side end of a positive electrode mixture layer. A length Y (mm) of a portion of the negative electrode mixture layer extending from the winding-start side end of the positive electrode mixture layer and a rate X (percent by mass) of the silicon compound with respect to the total mass of the negative electrode active material satisfy a relationship of Y≥3X−15 (6≤X≤15).

The present disclosure discloses a method for preparing an anode material for lithium ion battery of a SiC nanoparticle encapsulated by nitrogen-doped graphene. The method includes: in an ammonia atmosphere, heating a SiC nanoparticle for a predetermined time, and cooling to obtain the SiC nanoparticle encapsulated by nitrogen-doped graphene.

The present disclosure discloses a method for preparing an anode material for lithium ion battery of a SiC nanoparticle encapsulated by nitrogen-doped graphene. The method includes: in an ammonia atmosphere, heating a SiC nanoparticle for a predetermined time, and cooling to obtain the SiC nanoparticle encapsulated by nitrogen-doped graphene.