Provided is a secondary battery including: a positive electrode plate composed of an inorganic material containing a positive electrode active material in an oxide form and having a thickness of 25 μm or more; a negative electrode plate composed of an inorganic material containing a negative electrode active material in an oxide form and having a thickness of 25 μm or more; and an inorganic solid electrolyte, the secondary battery being charged and discharged at a temperature of 100° C. or higher.

Disclosed are electrochemical devices, such as sodium ion conducting solid state electrolytes, sodium battery electrodes, and solid-state sodium metal batteries including these electrodes and solid state electrolytes. One example method for preparing a sodium/sodium-β″-alumina interface with low interfacial resistance and capable of achieving high current density in an electrochemical cell includes the steps of: (a) providing a precursor electrolyte having a resistive surface region, wherein the precursor electrolyte comprises sodium-β″-alumina; (b) removing at least a portion of the resistive surface region; (c) heating the precursor electrolyte thereby forming a solid state electrolyte, and (d) placing a side of the solid state electrolyte in contact with a sodium anode.

A method for providing a miniature electrochemical cell having a total volume that is less than 0.5 cc is described. The cell casing is formed by joining two ceramic casing halves together. One or both casing halves are machined from ceramic to provide a recess that is sized and shaped to contain the electrode assembly. The opposite polarity terminals are electrically conductive feedthroughs or pathways, such as of gold, and are formed by brazing gold into tapered via holes machined into one or both ceramic casing halves. The two ceramic casing halves are separated from each other by a metal interlayer, such as of gold, bonded to a thin film metallization layer, such as of titanium, that contacts an edge periphery of each ceramic casing half. A solid electrolyte of LiPON (Li.sub.xPO.sub.yN.sub.z) is used to activate the electrode assembly.

High energy density and long cycle life all solid-state electrolyte lithium-ion batteries use ceramic-polymer composite anodes which include a polymer matrix with ceramic nanoparticles, silicon-based anode active materials, conducting agents, lithium salts and plasticizer distributed in the matrix. The silicon-based anode active material are anode active particles formed by high energy milling a mixture of silicon, graphite, and metallic and/or non-metallic oxides. A polymer coating is applied to the particles. The networking structure of the electrolyte establishes an effective lithium-ion transport pathway in the electrode and strengthens the contact between the electrode layer and solid-state electrolyte resulting in higher lithium-ion battery cell cycling stability and long battery life.

The sintered body has an average particle size in the range of 0.1 μm or more and 5 μm or less, includes gamet-type oxide base material particles having at least Li, La, and Zr, has 8% by volume or more of voids, and has an ionic conductivity of 1.0×10.sup.−5 S/cm or more at temperature of 25° C.

An all solid battery includes a solid electrolyte layer, a first electrode structure that has a structure in which a first electric collector layer of which a main component is a conductive material is sandwiched by two first electrode layers including an active material, and a second electrode structure that has a structure in which a second electric collector layer of which a main component is a conductive material is sandwiched by two second electrode layers including an active material. Roughness of interfaces between the first electric collector layer and the two first electrode layers and/or roughness of interfaces between the second electric collector layer and the two second electrode layers is larger than roughness of interfaces between the solid electrolyte layer, and the first electrode layer and the second electrode layer sandwiching the solid electrolyte layer.

A boron-containing proton-exchange solid support may include a proton-exchange solid support comprising an oxygen atom and a tetravalent boron-based acid group comprising a boron atom covalently bonded to the oxygen atom.

An all-solid secondary battery, including: a cathode; an anode; and a solid electrolyte layer disposed between the cathode and the anode, wherein the anode comprises an anode current collector; a first anode active material layer in contact with the anode current collector and comprising a first metal; a second anode active material layer disposed between the first anode active material layer and the solid electrolyte layer and comprising a carbon-containing active material; and a contact layer between the second anode active material layer and the solid electrolyte layer, and disposed such that the contact layer prevents contact between the second anode active material layer and the solid electrolyte layer, wherein the contact layer comprises a second metal, and has a thickness less than a thickness of the first anode active material layer.

A metal negative electrode and a method of making the metal negative electrode is disclosed. The metal negative electrode includes a metal negative electrode body and a protective layer formed on a surface of one side or each of two sides of the metal negative electrode body. The protective layer includes a liquid-state or gel-state inner layer that has an ability to dissolve alkali metal and a solid-state outer layer has a high ionic conductivity. The liquid-state or gel-state inner layer includes at least one of an aromatic hydrocarbon small molecule compound or a polymer containing an aromatic hydrocarbon group that each have an ability to accept an electron, and at least one of an ether small molecule solvent, an amine small molecule solvent, a thioether small molecule solvent, a polyether polymer, a polyamine polymer, or a polythioether polymer that each have an ability to complex lithium ions.

Disclosed is a power storage element including a positive electrode current collector layer and a negative electrode current collector layer which are arranged on the same plane and can be formed through a simple process. The power storage element further includes a positive electrode active material layer on the positive electrode current collector layer; a negative electrode active material layer on the negative electrode current collector layer; and a solid electrolyte layer in contact with at least the positive electrode active material layer and the negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are formed by oxidation treatment.