Provided is a solid electrolyte material comprising Li, Y, Br, and Cl wherein in an X-ray diffraction pattern in which Cu-Kα is used as a radiation source, peaks are present within all ranges of diffraction angles 2θ of 15.1° to 15.8°, 27.3° to 29.5°, 30.1° to 31.1°, 32.0° to 33.7°, 39.0° to 40.6°, and 47.0° to 48.5°.

The invention provides novel biocompatible upconversion nanoparticle (UCNP) that comprises a core of cubic nanocrystals (e.g., comprising α-Na Ln.sub.a, Ln.sub.b Ln.sub.c F.sub.4) and an epitaxial shell (e.g., formed from CaF.sub.2; wherein Ln.sub.b is Yb), and related methods of preparation and uses thereof.

The invention provides novel biocompatible upconversion nanoparticle (UCNP) that comprises a core of cubic nanocrystals (e.g., comprising α-Na Ln.sub.a, Ln.sub.b Ln.sub.c F.sub.4) and an epitaxial shell (e.g., formed from CaF.sub.2; wherein Ln.sub.b is Yb), and related methods of preparation and uses thereof.

Provided is a solid electrolyte material represented by a composition formula Li.sub.3−3δY.sub.1+δ−aM.sub.aCl.sub.6−x−yBr.sub.xI.sub.y, where M is at least one element selected from the group consisting of Al, Sc, Ga, and Bi; −1<δ<1; 0<a<2; 0<(1+δ−a); 0≤x≤6; 0≤y≤6; and (x+y)≤6.

Provided is a solid electrolyte material represented by a composition formula Li.sub.3−3δY.sub.1+δ−aM.sub.aCl.sub.6−x−yBr.sub.xI.sub.y, where M is at least one element selected from the group consisting of Al, Sc, Ga, and Bi; −1<δ<1; 0<a<2; 0<(1+δ−a); 0≤x≤6; 0≤y≤6; and (x+y)≤6.

A solid electrolyte material according to an aspect of the present disclosure is represented by the following Compositional Formula (1):

Li.sub.6-3zY.sub.zX.sub.6

where 0<z<2 is satisfied; and X represents Cl or Br.

A solid electrolyte material according to an aspect of the present disclosure is represented by the following Compositional Formula (1):

Li.sub.6-3zY.sub.zX.sub.6

where 0<z<2 is satisfied; and X represents Cl or Br.

A solid electrolyte material includes a first crystal phase. The first crystal phase has a composition that is deficient in Li as compared with a composition represented by the following composition formula (1).
Li.sub.3Y.sub.1Br.sub.6  formula (1)

A solid electrolyte material includes a first crystal phase. The first crystal phase has a composition that is deficient in Li as compared with a composition represented by the following composition formula (1).
Li.sub.3Y.sub.1Br.sub.6  formula (1)

Provided is a cathode material including a cathode active material; a coating layer which coats at least a part of a surface of the cathode active material, and which includes a first solid electrolyte material; and a second solid electrolyte material. The first solid electrolyte material includes Li, M, and X; however, does not include sulfur. M includes at least one element selected from the group consisting of metalloid elements and metal elements other than Li. X includes at least one element selected from the group consisting of Cl and Br.