A scintillation crystal can include Ln.sub.(1-y)RE.sub.yX.sub.3, wherein Ln represents a rare earth element, RE represents a different rare earth element, y has a value in a range of 0 to 1, and X represents a halogen. In an embodiment, RE is Ce, and the scintillation crystal is doped with Sr, Ba, or a mixture thereof at a concentration of at least approximately 0.0002 wt. %. In another embodiment, the scintillation crystal can have unexpectedly improved linearity and unexpectedly improved energy resolution properties. In a further embodiment, a radiation detection system can include the scintillation crystal, a photosensor, and an electronics device. Such a radiation detection system can be useful in a variety of radiation imaging applications.

Na-rich electrolyte compositions provided herein can be used in a variety of devices, such as sodium ionic batteries, capacitors and other electrochemical devices. Na-rich electrolyte compositions provided herein can have a chemical formula of Na.sub.3OX, Na.sub.3SX, Na .sub.(3-δ) M.sub.δ/2OX and Na .sub.(3-δ) M.sub.δ/2SX wherein 0<δ<0.8, wherein X is a monovalent anion selected from fluoride, chloride, bromide, iodide, H.sup.−, CN.sup.−, BF.sub.4.sup.−, BH.sub.4.sup.−, ClO.sub.4.sup.−, CH.sub.3.sup.−, NO.sub.2.sup.−, NH.sub.2.sup.− and mixtures thereof, and wherein M is a divalent metal selected from the group consisting of magnesium, calcium, barium, strontium and mixtures thereof. Na-rich electrolyte compositions provided herein can have a chemical formula of Na .sub.(3-δ) M.sub.δ/3OX and/or Na .sub.(3-δ) M.sub.δ/3SX; wherein 0<δ<0.5, wherein M is a trivalent cation M.sup.3, and wherein X is selected from fluoride, chloride, bromide, iodide, H.sup.−, CN.sup.−, BF.sub.4.sup.−, BH.sub.4.sup.−, ClO.sub.4.sup.−, CH.sub.3.sup.−, NO.sub.2.sup.−, NH.sup.2− and mixtures thereof. Synthesis and processing methods of NaRAP compositions for battery, capacitor, and other electrochemical applications are also provided.

Colloidal perovskite nanoplatelets can provide a material platform, with tunability extending from the deep UV, across the visible, into the near-IR. The high degree of spectral tunability can be achieved through variation of the cation, metal, and halide composition as well as nanoplatelet thickness.

A solid ion conductor, a solid electrolyte and an electrochemical device including the solid ion conductor, and a method of preparing the solid ion conductor are disclosed. The solid ion conductor may include a compound represented by Formula 1:
Li.sub.aM.sub.bM′.sub.cZr.sub.dX.sub.e  Formula 1 wherein, M is one or more metals of Na, K, Cs, Cu, or Ag, and having an oxidation state of +1, M′ is one or more lanthanide metals having an oxidation state of +3 and a crystal ionic radius of about 104 picometers to about 109 picometers, X is one or more halogen elements, 1<a<3.5, 0≤b<1, 0<c<1.5, 0<d<1.5, and 0<e<7.

A solid ion conductor compound represented by Formula 1:

Li.sub.xM1.sub.aM2.sub.bCl.sub.yBr.sub.z  Formula 1

wherein M1 is an alkali metal, an alkaline earth metal, a transition metal, or a combination thereof, M2 is a lanthanide element, or a combination thereof, 0<x<3.5, 0≤a<1.5, 0<b<1.5, 0<y<6, 0<z<6, and 0.166<y/z≤5.

An electrochromic device includes a light transmissive first substrate, a working electrode disposed on the first substrate, a light transmissive second substrate facing the first substrate, a counter electrode disposed on the second substrate, and a lithium-rich anti-perovskite (LiRAP) material disposed between the first and second substrates. The LiRAP material includes an ionically conductive and electrically insulating LiRAP material.

An electrochromic device includes a light transmissive first substrate, a working electrode disposed on the first substrate, a light transmissive second substrate facing the first substrate, a counter electrode disposed on the second substrate, and a lithium-rich anti-perovskite (LiRAP) material disposed between the first and second substrates. The LiRAP material includes an ionically conductive and electrically insulating LiRAP material.

A solid ion conductor, a solid electrolyte and an electrochemical device including the solid ion conductor, and a method of preparing the solid ion conductor are disclosed. The solid ion conductor may include a compound represented by Formula 1:

Li.sub.aM.sub.bM′.sub.cZr.sub.dX.sub.e   Formula 1

wherein, M is one or more metals of Na, K, Cs, Cu, or Ag, and having an oxidation state of +1, M′ is one or more lanthanide metals having an oxidation state of +3 and a crystal ionic radius of about 104 picometers to about 109 picometers, X is one or more halogen elements, 1<a<3.5, 0≤b<1, 0<c<1.5, 0<d<1.5, and 0<e<7.

An electrochromic device includes a light transmissive first substrate, a working electrode disposed on the first substrate, a light transmissive second substrate facing the first substrate, a counter electrode disposed on the second substrate, and a lithium-rich anti-perovskite (LiRAP) material disposed between the first and second substrates. The LiRAP material includes an ionically conductive and electrically insulating LiRAP material.

Cold sintering of materials includes using a process of combining at least one inorganic compound, e.g., ceramic, in particle form with a solvent that can partially solubilize the inorganic compound to form a mixture; and applying pressure and a low temperature to the mixture to evaporate the solvent and densify the at least one inorganic compound to form sintered materials.