An object is to improve the characteristics of a power storage device such as a charging and discharging rate or a charge and discharge capacity. The grain size of particles of a positive electrode active material is nano-sized so that a surface area per unit mass of the active material is increased. Specifically, the grain size is set to greater than or equal to 10 nm and less than or equal to 100 nm, preferably greater than or equal to 20 nm and less than or equal to 60 nm. Alternatively, the surface area per unit mass is set to 10 m.sup.2/g or more, preferably 20 m.sup.2/g or more. Further, the crystallinity of the active material is increased by setting an XRD half width to greater than or equal to 0.12 and less than 0.17, preferably greater than or equal to 0.13 and less than 0.16.

An object is to improve the characteristics of a power storage device such as a charging and discharging rate or a charge and discharge capacity. The grain size of particles of a positive electrode active material is nano-sized so that a surface area per unit mass of the active material is increased. Specifically, the grain size is set to greater than or equal to 10 nm and less than or equal to 100 nm, preferably greater than or equal to 20 nm and less than or equal to 60 nm. Alternatively, the surface area per unit mass is set to 10 m.sup.2/g or more, preferably 20 m.sup.2/g or more. Further, the crystallinity of the active material is increased by setting an XRD half width to greater than or equal to 0.12 and less than 0.17, preferably greater than or equal to 0.13 and less than 0.16.

The disclosure describes an exemplary binding layer formed on Aluminum (Al) substrate that binds the substrate with a coated material. Additionally, an extended form of the binding layer is described. By making a solution containing Al-transition metal elements-PO, the solution can be used in slurry making (the slurry contains active materials) in certain embodiments. The slurry can be coated on Al substrate followed by heat treatment to form a novel electrode. Alternatively, in certain embodiments, the solution containing Al-transition metal elements-PO can be mixed with active material powder, after heat treatment, to form new powder particles bound by the binder.

The disclosure describes an exemplary binding layer formed on Aluminum (Al) substrate that binds the substrate with a coated material. Additionally, an extended form of the binding layer is described. By making a solution containing Al-transition metal elements-PO, the solution can be used in slurry making (the slurry contains active materials) in certain embodiments. The slurry can be coated on Al substrate followed by heat treatment to form a novel electrode. Alternatively, in certain embodiments, the solution containing Al-transition metal elements-PO can be mixed with active material powder, after heat treatment, to form new powder particles bound by the binder.

A three-dimensional all-solid-state lithium ion batteries including a cathode protection layer, the battery including: a cathode including a plurality of plates which are vertically disposed on a cathode current collector; a cathode protection layer disposed on a surfaces of the cathode and the cathode current collector; a solid state electrolyte layer disposed on the cathode protection layer; an anode disposed on the solid state electrolyte layer; and an anode current collector disposed on the anode, wherein the cathode protection layer is between the cathode and the solid state electrolyte layer, and wherein the solid state electrolyte layer is between the cathode protection layer and the anode.

The present invention provides a positive electrode active substance for a secondary cell, the positive electrode active substance capable of suppressing adsorption of water effectively in order to obtain a high-performance lithium ion secondary cell or sodium ion secondary cell. The present invention also provides a method for producing the positive electrode active substance for a secondary cell. That is, the present invention is a positive electrode active substance for a secondary cell, in which one or two selected from the group consisting of a water-insoluble electrically conductive carbon material and carbon obtained by carbonizing a water-soluble carbon material, and 0.1 to 5 mass % of a metal fluoride are supported on a compound containing at least iron or manganese, the compound represented by formula (A) LiFe.sub.aMn.sub.bM.sup.1.sub.cPO.sub.4, formula (B) Li.sub.2Fe.sub.dMn.sub.eM.sup.2.sub.fSiO.sub.4, or formula (C) NaFe.sub.gMn.sub.hQ.sub.iPO.sub.4.

The present invention provides a positive electrode active substance for a secondary cell, the positive electrode active substance capable of suppressing adsorption of water effectively in order to obtain a high-performance lithium ion secondary cell or sodium ion secondary cell. The present invention also provides a method for producing the positive electrode active substance for a secondary cell. That is, the present invention is a positive electrode active substance for a secondary cell, in which one or two selected from the group consisting of a water-insoluble electrically conductive carbon material and carbon obtained by carbonizing a water-soluble carbon material, and 0.1 to 5 mass % of a metal fluoride are supported on a compound containing at least iron or manganese, the compound represented by formula (A) LiFe.sub.aMn.sub.bM.sup.1.sub.cPO.sub.4, formula (B) Li.sub.2Fe.sub.dMn.sub.eM.sup.2.sub.fSiO.sub.4, or formula (C) NaFe.sub.gMn.sub.hQ.sub.iPO.sub.4.

The invention relates to a method for producing a porous electrode, said electrode comprising a layer deposited on a substrate, said layer being binder-free and having a porosity of more than 30 volume %, and preferably less than 50 volume %, and pores having an average diameter of less than 50 nm, said method being characterized in that: (a) a colloidal suspension is provided, containing aggregates or agglomerates of nanoparticles of at least one material P having an average primary diameter D.sub.50 of less than or equal to 80 nm, and preferably less than or equal to 50 nm, said aggregates or agglomerates having an average diameter comprised between 80 nm and 300 nm (preferably between 100 nm and 200 nm), (b) a substrate is provided, (c) a porous, preferably mesoporous, electrode layer is deposited on said substrate by electrophoresis, by ink-jet, by doctor blade, by roll coating, by curtain coating or by dip-coating, from said colloidal suspension provided in step (a); (d) said layer obtained in step (c) is dried, preferably in an air flow, (e) optionally, consolidation of the porous, preferably mesoporous electrode layer obtained in step (d) by pressing and/or heating.

The invention relates to a method for producing a porous electrode, said electrode comprising a layer deposited on a substrate, said layer being binder-free and having a porosity of more than 30 volume %, and preferably less than 50 volume %, and pores having an average diameter of less than 50 nm, said method being characterized in that: (a) a colloidal suspension is provided, containing aggregates or agglomerates of nanoparticles of at least one material P having an average primary diameter D.sub.50 of less than or equal to 80 nm, and preferably less than or equal to 50 nm, said aggregates or agglomerates having an average diameter comprised between 80 nm and 300 nm (preferably between 100 nm and 200 nm), (b) a substrate is provided, (c) a porous, preferably mesoporous, electrode layer is deposited on said substrate by electrophoresis, by ink-jet, by doctor blade, by roll coating, by curtain coating or by dip-coating, from said colloidal suspension provided in step (a); (d) said layer obtained in step (c) is dried, preferably in an air flow, (e) optionally, consolidation of the porous, preferably mesoporous electrode layer obtained in step (d) by pressing and/or heating.

Provided is a method for producing a cathode that is configured to decrease battery resistance when it is used in an all-solid-state battery. The cathode includes a cathode layer containing composite cathode active material particles and solid electrolyte particles. At least one of the composite cathode active material particles and the solid electrolyte particles contain a sulfur element. In a photoelectron spectrum by X-ray photoelectron spectroscopy measurement of the cathode layer, an S peak intensity ratio (C/D), which is derived from the sulfur element, of a signal intensity C at a binding energy of 161.6 eV to a signal intensity D at a binding energy of 163.1 eV, is larger than 0.78.