Provided is a battery in which the internal resistance is further decreased. The present disclosure provides a battery, comprising a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode. The electrolyte layer includes a first solid electrolyte material. The first solid electrolyte material includes Li, M, and X, and does not include sulfur. M is at least one selected from the group consisting of metalloid elements and metal elements other than Li. X is at least one selected from the group consisting of Cl, Br, and I. The negative electrode includes a negative electrode active material and a sulfide solid electrolyte.

Provided is a battery having further improved charging/discharging efficiency. The battery comprises a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode. The electrolyte layer includes a first electrolyte layer and a second electrolyte layer. The second electrolyte layer is provided between the first electrolyte layer and the negative electrode. The first electrolyte layer includes a first solid electrolyte material. The second electrolyte layer includes a second solid electrolyte material that is a material different from the first solid electrolyte material. The first solid electrolyte material includes Li, M, and X and does not include sulfur. M includes at least one selected from the group consisting of metalloid elements and metal elements other than Li. X is at least one selected from the group consisting of Cl, Br, and I. The reduction potential with regard to lithium of the second solid electrolyte material is lower than the reduction potential with regard to lithium of the first solid electrolyte material.

The solid electrolyte material of the present disclosure consists of Li, M1, M2, and X, wherein M1 is at least two selected from the group consisting of Ca, Mg, and Zn; M2 is at least one selected from the group consisting of Y, Gd, and Sm; and X is at least one selected from the group consisting of F, Cl, Br, and I.

Sodium-based all solid-state batteries exhibit improved battery cycle life and stability with the use of a new chloride-based sodium solid electrolyte in which sodium diffusivity within the electrolyte is enhanced through substitution of atoms including one or more of Y with Zr, Ti, Hf, Ta, and Na with one or more of Ca and Sr.

An object of the present disclosure is to provide an all solid fluoride ion battery that has a favorable capacity property. The present disclosure achieves the object by providing an all solid fluoride ion battery comprising: a cathode layer, an anode layer, and a solid electrolyte layer formed between the cathode layer and the anode layer; wherein the anode layer includes a metal fluoride containing an M1 element, an M2 element, and a F element; the M1 element is a metal element that fluorination and defluorination occur at a potential, versus Pb/PbF.sub.2, of −2.5 V or more; the M2 element is a metal element that neither fluorination nor defluorination occur at a potential, versus Pb/PbF.sub.2, of −2.5 V or more; and the M2 element is a metal element that, when in a form of a fluoride, fluoride ion conductivity is 1×10.sup.−4 S/cm or more at 200° C.

An object of the present disclosure is to provide an all solid fluoride ion battery that has a favorable capacity property. The present disclosure achieves the object by providing an all solid fluoride ion battery comprising: a cathode layer, an anode layer, and a solid electrolyte layer formed between the cathode layer and the anode layer; wherein the anode layer includes a metal fluoride containing an M1 element, an M2 element, and a F element; the M1 element is a metal element that fluorination and defluorination occur at a potential, versus Pb/PbF.sub.2, of −2.5 V or more; the M2 element is a metal element that neither fluorination nor defluorination occur at a potential, versus Pb/PbF.sub.2, of −2.5 V or more; and the M2 element is a metal element that, when in a form of a fluoride, fluoride ion conductivity is 1×10.sup.−4 S/cm or more at 200° C.

A solid electrolyte material of the present disclosure includes Li, M1, M2, and X. The M1 is at least one element selected from the group consisting of a group 2 element and a group 12 element. The M2 is at least three elements selected from the group consisting of a rare-earth element and a group 13 element. The X is at least one selected from the group consisting of F, Cl, Br, and I. A battery of the present disclosure includes a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer includes the solid electrolyte material of the present disclosure.

A solid electrolyte material of the present disclosure consists of Li, M1, M2, and X. The M1 is one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. The M2 is at least one selected from the group consisting of Gd and Sm. The X is at least one selected from the group consisting of F, Cl, Br, and I. A battery of the present disclosure includes a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer includes the solid electrolyte material of the present disclosure.

Provided is a battery comprising a cathode, an anode, and an electrolyte layer. The electrolyte layer includes a first electrolyte layer and a second electrolyte layer. The first electrolyte layer includes a first solid electrolyte material. The second electrolyte layer includes a second solid electrolyte material which is different from the first solid electrolyte material. The first solid electrolyte material includes lithium, at least one kind selected from the group consisting of metalloid elements and metal elements other than lithium, and at least one kind selected from the group consisting of chlorine and bromine. The first solid electrolyte material does not include sulfur.

Synthesizing upconverting nanoparticles includes heating a precursor solution comprising one or more rare earth salts, an alkali metal salt or alkaline earth salt, and a solvent comprising a plasticizer in a microwave reactor to yield a product mixture, and cooling the product mixture to yield the upconverting nanoparticles. Core-shell upconverting nanoparticles are synthesized by combining the upconverting nanoparticles with a precursor solution comprising one or more rare earth salts, an alkali metal salt or alkaline earth salt, and a solvent comprising a plasticizer to yield a nanoparticle mixture, heating the nanoparticle mixture in a microwave reactor to yield a product mixture, and cooling the product mixture to yield the core-shell upconverting nanoparticles.