A secondary battery with a positive electrode plate having a metallic positive electrode core body and positive electrode active material layers formed on both surfaces of the positive electrode core body. The positive electrode core body has an active material layer-free region in which the positive electrode active material layers are not formed on the surface of the positive electrode core body, wherein a first protrusion protruding in the thickness direction of the positive electrode core body from one surface of the positive electrode core body is formed at the end of the active material layer-free region, positive electrode protection layers are formed in a portion adjacent to the positive electrode active material layers on one surface of the positive electrode core body in the active material layer-free region, and the protrusion height T1 of the first protrusion is less than the thickness T2 of the positive electrode protection layer.

A secondary battery provided with: a belt-like positive electrode plate having a plurality of positive electrode tabs; and a positive electrode current collector which is connected so that the plurality of positive electrode tabs are stacked, wherein the positive electrode plate has a positive electrode core body and a positive electrode active material layer formed on the positive electrode core bodies. At one edge side of the positive electrode plate where the plurality of positive electrode tabs are provided, one surface of the positive electrode core body has formed thereon a first protrusion that protrudes from said surface of the positive electrode core body in the thickness direction of the positive electrode core body, whereas the other surface of the positive electrode core body has no protrusion formed to protrude from said other surface of the positive electrode core body in the thickness direction of the positive electrode core body.

The present invention is directed to a silicon-containing particle for use as a negative-electrode active material of a non-aqueous electrolyte secondary battery, wherein a crystal grain size is 300 nm or less, the crystal grain size being obtained by a Scherrer method from a full width at half maximum of a diffraction line attributable to Si (111) and near 2θ=28.4° in an x-ray diffraction pattern analysis, and a true density is more than 2.320 g/cm.sup.3 and less than 3.500 g/cm.sup.3. The invention provides silicon-containing particles for use as a negative-electrode active material of a non-aqueous electrolyte secondary battery that enable manufacture of a non-aqueous electrolyte secondary battery having an excellent cycle characteristics and a higher capacity compared with graphite types.

A positive active material for a rechargeable lithium battery includes a compound represented by Chemical Formula 1, Li.sub.aNi.sub.xCo.sub.yMe.sub.zM.sup.1.sub.kM.sup.2.sub.pO.sub.2 wherein, 0.9≦a≦1.1, 0.7≦x≦0.93, 0<y≦0.3, 0<z≦0.3, 0.001≦k≦0.006, 0.001 ≦p≦0.005, x+y+z+k+p=1, Me is Mn or Al, M.sup.1 is a divalent element, and M.sup.2 is a tetravalent element.

A seawater battery includes an anode and a cathode corresponding to the anode. The cathode cooperates with the anode to produce a current and includes a metal substrate and a mixture coating layer. The mixture coating layer covered on the metal substrate includes a conductive polymer material and a plurality of carbon nanotubes mixed with the conductive polymer material.

A seawater battery includes an anode and a cathode corresponding to the anode. The cathode cooperates with the anode to produce a current and includes a metal substrate and a mixture coating layer. The mixture coating layer covered on the metal substrate includes a conductive polymer material and a plurality of carbon nanotubes mixed with the conductive polymer material.

A Mg battery has a positive-electrode can, a positive-electrode pellet made of a positive-electrode active material or the like, a positive electrode composed of a metallic net supporting body, a negative-electrode cup, a negative electrode made of a negative-electrode active material, and a separator impregnated with an electrolytic solution and disposed between the positive-electrode pellet and the negative-electrode active material. By adopting a structure that copper contacts the positive-electrode active material, the electrochemical device can be given a large discharge capacity.

This invention provides a non-aqueous electrolyte magnesium secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, the non-aqueous electrolyte comprising [N(SO.sub.2CF.sub.3).sub.2].sup.− as an anion, and Mg.sup.2+ and/or an organic onium cation as a cation.

Li-ion batteries are provided that include a cathode, an anode comprising active particles, an electrolyte ionically coupling the anode and the cathode, a separator electrically separating the anode and the cathode, and at least one hydrofluoric acid neutralizing agent incorporated into the anode or the separator. Li-ion batteries are also provided that include a cathode, an anode comprising active particles, an electrolyte ionically coupling the anode and the cathode, and a separator electrically separating the anode and the cathode, where the electrolyte may be formed from a mixture of an imide salt and at least one salt selected from the group consisting of LiPF.sub.6, LiBF.sub.4, and LiClO.sub.4. Li-ion battery anodes are also provided that include an active material core and a protective coating at least partially encasing the active material core, where the protective coating comprises a material that is resistant to hydrofluoric acid permeation.

Electrochemical cells operating with molten electrodes and electrolyte, where the cathode is an alloy of a metal and metalloid, may be assembled in a discharged state by combining first an anodic metal with a cathodic metal to form a binary alloy. This binary alloy is then placed in a cell housing with the metalloid and the electrolyte, all in the solid state. The temperature is raised to, and maintained at, a temperature above the melting point of the highest melting component until components assembled into horizontal layers of electrolyte above a layer of a ternary alloy formed by the combination of the binary alloy and the metalloid. A charge and discharged cycle is then run through the electrochemical cell.