A battery comprising an acidified metal oxide (“AMO”) material, preferably in monodisperse nanoparticulate form 20 nm or less in size, having a pH <7 when suspended in a 5 wt % aqueous solution and a Hammett function H.sub.0 >−12, at least on its surface.

A storage device having excellent cycle lifetime, an electrode used in this storage device, and a production method of the electrode are provided. An electrode comprising an active material and a conductive carbon including oxidized carbon. A surface of the active material is covered by the conductive carbon. A Raman spectrum of the active material covered by the conductive carbon includes a peak intensity (a) derived from the active material and a peak intensity (b) of D-band derived from the conductive carbon. A peak intensity ratio (b)/(a) between the peak intensity (a) and the peak intensity (b) is 0.25 or more.

A zinc ion battery includes a cathode; an anode; a separator; and an electrolyte sandwiched between the cathode and the anode. The electrolyte includes a mixture of zinc perchlorate and sodium perchlorate, and a ratio of the sodium perchlorate to zinc perchlorate is at least 30.

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 %.

A negative electrode plate includes: a current collector; and a negative electrode framework located on the current collector, where the negative electrode framework includes at least a first negative electrode framework layer and a second negative electrode framework layer, the first negative electrode framework layer is located between the current collector and the second negative electrode framework layer, and a porosity of the first negative electrode framework layer is higher than a porosity of the second negative electrode framework layer. With this design, side reactions between lithium metal and an electrolyte can be reduced, formation of lithium dendrites can be inhibited, and drastic swelling and contraction of the negative electrode plate in volume due to intercalation and deintercalation of lithium ions can be greatly alleviated or even eliminated, thereby improving safety and stability of the electrochemical apparatus.

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).

An anode for a secondary battery including an anode active material and a secondary battery including the anode and having improved stability and reduced resistance are disclosed. In an aspect, the anode active material includes a silicon-based active material having a specific surface area (BET) in a range from 0.5 m.sup.2/g to 5 m.sup.2/g, a first carbon-based active material having an average particle diameter (D50) in a range from 1 μm to 4 μm, and a second carbon-based active material having an average particle diameter greater than that of the first carbon-based active material.

Composites comprising an exfoliated graphite support material having a degree of graphitization g in an range of 50 to 93%, obtained by XRD Rietveld analysis, which is coated with ZnO nanoparticles. These composites are produced by three different methods: A) (syn) the method comprises the following consecutive steps: i) a Zn(II)salt is dissolved in a solvent ii) graphite and a base are added simultaneously iii) the mixture is stirred under impact of ultrasound iv) the solvent is removed from the suspension or B) (pre) the method comprises the following consecutive steps: i) graphite is suspended in a solvent and exfoliated via impact of ultrasound ii) a Zn(II)salt and a base are added simultaneously forming nano-ZnO particles iii) the mixture is stirred iv) the solvent is removed from the suspension or C) (post) the method comprises the following steps: i) a Zn(II)salt and a base are mixed in a solvent in a first reactor forming nano-ZnO particles ii) graphite is exfoliated via impact of ultrasound in a second reactor iii) both suspensions of i) and ii) are mixed together iv) after step iii) the solvent is removed from the suspension. These coated composites may be tempered in a further step and again coated and again tempered.

Composites comprising an exfoliated graphite support material having a degree of graphitization g in an range of 50 to 93%, obtained by XRD Rietveld analysis, which is coated with ZnO nanoparticles. These composites are produced by three different methods: A) (syn) the method comprises the following consecutive steps: i) a Zn(II)salt is dissolved in a solvent ii) graphite and a base are added simultaneously iii) the mixture is stirred under impact of ultrasound iv) the solvent is removed from the suspension or B) (pre) the method comprises the following consecutive steps: i) graphite is suspended in a solvent and exfoliated via impact of ultrasound ii) a Zn(II)salt and a base are added simultaneously forming nano-ZnO particles iii) the mixture is stirred iv) the solvent is removed from the suspension or C) (post) the method comprises the following steps: i) a Zn(II)salt and a base are mixed in a solvent in a first reactor forming nano-ZnO particles ii) graphite is exfoliated via impact of ultrasound in a second reactor iii) both suspensions of i) and ii) are mixed together iv) after step iii) the solvent is removed from the suspension. These coated composites may be tempered in a further step and again coated and again tempered.

A negative electrode active material containing a negative electrode active material particle which includes a silicon compound particle containing a silicon compound (SiO.sub.x: 0.5≤x≤1.6). The silicon compound particle has three or more peaks in a chemical shift value ranging from −40 ppm to −120 ppm but has no peak in a chemical shift value within a range of −65±3 ppm in a spectrum obtained from .sup.29Si-MAS-NMR of the silicon compound particle. This provides a negative electrode active material capable of improving cycle characteristics when it is used as a negative electrode active material for a secondary battery.