Provided is a solid electrolyte material represented by the following composition formula (1):

Li.sub.3YX.sub.6Formula (1) where X is two or more kinds of elements selected from the group consisting of Cl, Br, and I.

Provided is a solid electrolyte material represented by the following composition formula (1):

Li.sub.3YX.sub.6Formula (1) where X is two or more kinds of elements selected from the group consisting of Cl, Br, and I.

A solid electrolyte material is represented by the following compositional formula (1):

Li.sub.3-3-2aY.sub.1+-aM.sub.aCl.sub.6-x-yBr.sub.xI.sub.y where, M is at least one selected from the group consisting of Ta and Nb; and 1<<1, 0<a<1.2, 0<(332a), 0<(1+a), 0x6, 0y6, and (x+y)6 are satisfied.

A solid electrolyte material contains Li; Y; at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Zr, Nb, and Ta; and at least one selected from the group consisting of Cl, Br, and I. An X-ray diffraction pattern of the solid electrolyte material obtained using Cu-K radiation as an X-ray source includes peaks in a range of diffraction angles 2 of 30 or more and 33 or less, in a range of diffraction angles 2 of 39 or more and 43 or less, and in a range of diffraction angles 2 of 47 or more and 51 or less.

Provided is a solid electrolyte material represented by the following composition formula (1):

Li.sub.6-3dY.sub.dX.sub.6Formula (1) where X is two or more kinds of elements selected from the group consisting of Cl, Br, and I; and 0<d<2.

Ligand-capped inorganic particles, films composed of the ligand-capped inorganic particles, and methods of patterning the films are provided. Also provided are electronic, photonic, and optoelectronic devices that incorporate the films. The ligands that are bound to the inorganic particles are composed of a cation/anion pair. The anion of the pair is bound to the surface of the particle and at least one of the anion and the cation is photosensitive.

A fluoride ion battery in which an occurrence of a short circuit is suppressed achieves the object by providing a fluoride ion battery including: an electrode layer that includes a first metal element or a carbon element and has capability of fluorination and defluorination; a solid electrolyte layer containing a solid electrolyte material, the solid electrolyte material including a second metal element with lower fluorination potential and defluorination potential than the potentials of the first metal element or the carbon element; and an anode current collector, in this order; and an anode active material layer being not present between the solid electrolyte layer and the anode current collector; and at least one of the solid electrolyte layer and the anode current collector includes a simple substance of Pb, Sn, In, Bi, or Sb, or an alloy containing one or more of these metal elements.

Provided is a solid electrolyte material represented by the following composition formula (1):

Li.sub.33d(Y.sub.1xM.sub.x).sub.1+dX.sub.6 Formula (1) where M is an element having an ionic radius larger than that of Y; X is at least one kind of element selected from the group consisting of F, Cl, Br and I; 0<x1; and 0.15d0.15.

Provided is a solid electrolyte material represented by the following composition formula (1):

Li.sub.33d(Y.sub.1xM.sub.x).sub.1+dX.sub.6 Formula (1) where M is an element having an ionic radius larger than that of Y; X is at least one kind of element selected from the group consisting of F, Cl, Br and I; 0<x1; and 0.15d0.15.

A main object of the present disclosure is to provide a solid electrolyte with high fluoride ion conductivity. The present disclosure achieves the object by providing a solid electrolyte to be used for a fluoride ion battery, the solid electrolyte comprising: a composition of Ce.sub.1-x-yLa.sub.xSr.sub.yF.sub.3-y, in which 0<x, 0<y, and 0<x+y<1; and a crystal phase that has a Tysonite structure.