A secondary battery with excellent cycle performance is provided. The secondary battery is an all-solid-state battery including a positive electrode current collector layer, a base film, a positive electrode active material layer, a buffer layer, and a solid electrolyte layer. The base film contains titanium nitride. The positive electrode active material layer contains lithium cobalt oxide. The buffer layer contains titanium oxide. The solid electrolyte layer contains a titanium compound. By using titanium oxide for the buffer layer, a side reaction between the positive electrode active material layer and the solid electrolyte layer can be suppressed, and cycle performance can be improved.

A secondary battery with excellent cycle performance is provided. The secondary battery is an all-solid-state battery including a positive electrode current collector layer, a base film, a positive electrode active material layer, a buffer layer, and a solid electrolyte layer. The base film contains titanium nitride. The positive electrode active material layer contains lithium cobalt oxide. The buffer layer contains titanium oxide. The solid electrolyte layer contains a titanium compound. By using titanium oxide for the buffer layer, a side reaction between the positive electrode active material layer and the solid electrolyte layer can be suppressed, and cycle performance can be improved.

An object is to provide an electrode active material that can provide an alkali metal battery having a longer charge/discharge life and a higher capacity. The problem is solved by means of an electrode active material for an alkali metal battery, represented by formula: A.sub.a1MS.sub.a2X.sub.a3 wherein A is selected from Li and Na; M is selected from V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W which are group 4 to 6 elements; X is selected from F, Cl, Br, I, CO.sub.3, SO.sub.4, NO.sub.3, BH.sub.4, BF.sub.4, PF.sub.6, ClO.sub.4, CF.sub.3SO.sub.3, (CF.sub.3SO.sub.2).sub.2N, (C.sub.2F.sub.5SO.sub.2).sub.2N, (FSO.sub.2).sub.2N, and [B(C.sub.2O.sub.4).sub.2]; a1 is 1 to 9; a2 is 2 to 6; when a3 is 3 and a3 is 0, a2 is not 4; and when M does not include V, a3>0.

A positive electrode active material for an all-solid-state lithium ion secondary battery, containing: a lithium-metal composite oxide particle having a niobium solid solution layer and a center other than the niobium solid solution layer; and a coating layer coating at least a part of a surface of the lithium-metal composite oxide particle and formed of a compound containing lithium and niobium, an average thickness of the coating layer is 2 nm or more and 1 μm or less, and an average thickness of the niobium solid solution layer is 0.5 nm or more and 20 nm or less.

An object of the present invention is to provide a sulfide solid electrolyte having a reduced specific surface area; an electrode composite material, a slurry and a solid battery, in each of which the sulfide solid electrolyte is used; and a method of producing the sulfide solid electrolyte, and the present invention provides a sulfide solid electrolyte containing lithium (Li), phosphorus (P) and sulfur (S) elements, and also containing a crystal phase having peaks at positions of 2θ=23.2°±1.00° and 29.2°±0.500° in an X-ray diffraction pattern measured with CuKα1 radiation.

An object of the present invention is to provide a sulfide solid electrolyte having a reduced specific surface area; an electrode composite material, a slurry and a solid battery, in each of which the sulfide solid electrolyte is used; and a method of producing the sulfide solid electrolyte, and the present invention provides a sulfide solid electrolyte containing lithium (Li), phosphorus (P) and sulfur (S) elements, and also containing a crystal phase having peaks at positions of 2θ=23.2°±1.00° and 29.2°±0.500° in an X-ray diffraction pattern measured with CuKα1 radiation.

Provided is an all-solid-state battery module including: an all-solid-state battery with a voltage in excess of 0 V; a switching element connected in series with the all-solid-state battery; a control unit that controls on/off of the switching element; and a trigger input path connected to the control unit, where a trigger that causes the switching element to transition to an on state is input via the trigger input path.

A solid electrolyte material according to the present disclosure includes Li, DC, Y, Sm, and X. The DC is at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. The X is at least one selected from the group consisting of F, Cl, Br, and I. A battery according to 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 according to the present disclosure.

A solid electrolyte material according to the present disclosure includes Li, DC, Y, Sm, and X. The DC is at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. The X is at least one selected from the group consisting of F, Cl, Br, and I. A battery according to 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 according to the present disclosure.

There is provided a sulfide solid electrolyte containing elemental lithium (Li), elemental phosphorus (P), elemental sulfur (S), and an elemental halogen (X). The mole ratio of the elemental lithium (Li) to the elemental phosphorus (P), Li/P, satisfies 3.7<Li/P<5.4. The mole ratio of the elemental sulfur (S) to the elemental phosphorus (P), S/P, satisfies 3.9<S/P<4.1. The mole ratio of the elemental halogen (X) to the elemental phosphorus (P), X/P, satisfies 0.7<X/P<2.4. The sulfide solid electrolyte includes a crystalline phase having an argyrodite-type crystal structure.