A method of treating mercury-contaminated material to obtain a treated product having reduced mercury leachability includes the steps of (a) admixing the mercury-contaminated material with a reagent system comprising calcium sulfide (CaS) and trisodium phosphate (TNaP), wherein the calcium sulfide and trisodium phosphate are preferably provided at a CaS:TNaP ratio of from 2:1 to 1:2, on a dry weight reagent basis, and the reagent system is preferably provided in an amount equal to 0.4% to 5% by weight of the contaminated material; and (b) adding water as needed to achieve a moisture content of at least 5% by weight of the contaminated material.

Embodiments of the present application relate to a solid electrolyte and a preparation method thereof, and an electrochemical device and an electronic device comprising the same. The solid electrolyte of the present application includes a solid electrolyte material being represented by the chemical formula of Li.sub.1+2x2yM.sub.yGa.sub.2+xP.sub.1xS.sub.6, where M is selected from the group consisting of Sr, Ba, Zn, Cd and a combination thereof, 0x0.2 and 0y0.05. Embodiments of the present application provides a solid electrolyte having good stability with lithium and ionic conductivity by forming the solid electrolyte using lower cost solid electrolyte materials and optimizing the material composition and a crystal structure thereof. At the same time, this also reduces the manufacturing costs of the solid electrolyte, and improves the structural stability of the solid electrolyte.

Embodiments of the present application relate to a solid electrolyte and a preparation method thereof, and an electrochemical device and an electronic device comprising the same. The solid electrolyte of the present application includes a solid electrolyte material being represented by the chemical formula of Li.sub.1+2x2yM.sub.yGa.sub.2+xP.sub.1xS.sub.6, where M is selected from the group consisting of Sr, Ba, Zn, Cd and a combination thereof, 0x0.2 and 0y0.05. Embodiments of the present application provides a solid electrolyte having good stability with lithium and ionic conductivity by forming the solid electrolyte using lower cost solid electrolyte materials and optimizing the material composition and a crystal structure thereof. At the same time, this also reduces the manufacturing costs of the solid electrolyte, and improves the structural stability of the solid electrolyte.

A positive electrode active material for a lithium-sulfur battery, and more particularly, to a positive electrode active material for a lithium-sulfur battery including metal sulfide nanoparticles and a preparation method thereof. The metal sulfide nanoparticles with large specific surface area applied to the positive electrode active material for the lithium-sulfur battery according to the present invention acts as a redox mediator during charging and discharging of the lithium-sulfur battery, thereby reducing the shuttle response by not only inhibiting the formation itself of polysulfides with elution properties, but also, even if polysulfides are eluted, adsorbing them and thus preventing them from diffusing into the electrolyte solution, and thus the capacity and life characteristics of the lithium-sulfur battery can be improved.

A positive electrode active material for a lithium-sulfur battery, and more particularly, to a positive electrode active material for a lithium-sulfur battery including metal sulfide nanoparticles and a preparation method thereof. The metal sulfide nanoparticles with large specific surface area applied to the positive electrode active material for the lithium-sulfur battery according to the present invention acts as a redox mediator during charging and discharging of the lithium-sulfur battery, thereby reducing the shuttle response by not only inhibiting the formation itself of polysulfides with elution properties, but also, even if polysulfides are eluted, adsorbing them and thus preventing them from diffusing into the electrolyte solution, and thus the capacity and life characteristics of the lithium-sulfur battery can be improved.

The present disclosure relates to a sulfide-based solid electrolyte doped with an alkaline earth metal for improving the ionic conductivity thereof and a method of manufacturing the same. The sulfide-based solid electrolyte is represented by Chemical Formula 1 below. The sulfide-based solid electrolyte exhibits high voltage stability and ionic conductivity. Consequently, it is possible to obtain an all-solid-state battery having a large capacity and stable behavior using the sulfide-based solid electrolyte.

Li.sub.6-2xMe.sub.xPS.sub.5Ha [Chemical Formula 1] wherein Me is an alkaline earth metal element, Ha is a halogen element, and 0<x0.5.

The present disclosure relates to a sulfide-based solid electrolyte doped with an alkaline earth metal for improving the ionic conductivity thereof and a method of manufacturing the same. The sulfide-based solid electrolyte is represented by Chemical Formula 1 below. The sulfide-based solid electrolyte exhibits high voltage stability and ionic conductivity. Consequently, it is possible to obtain an all-solid-state battery having a large capacity and stable behavior using the sulfide-based solid electrolyte.

Li.sub.6-2xMe.sub.xPS.sub.5Ha [Chemical Formula 1] wherein Me is an alkaline earth metal element, Ha is a halogen element, and 0<x0.5.

Provided is a magnesium secondary battery including a positive electrode member 23 including at least a positive electrode active material layer 23B, a separator 24 disposed facing the positive electrode member 23, a negative electrode member 25 containing magnesium or a magnesium compound disposed facing the separator 24, and an electrolytic solution containing a magnesium salt. The positive electrode active material layer 23B includes magnesium sulfide having a zinc blende type crystal structure.

A positive electrode active material for a lithium-sulfur battery, and more particularly, to a positive electrode active material for a lithium-sulfur battery including metal sulfide nanoparticles and a preparation method thereof. The metal sulfide nanoparticles with large specific surface area applied to the positive electrode active material for the lithium-sulfur battery according to the present invention acts as a redox mediator during charging and discharging of the lithium-sulfur battery, thereby reducing the shuttle response by not only inhibiting the formation itself of polysulfides with elution properties, but also, even if polysulfides are eluted, adsorbing them and thus preventing them from diffusing into the electrolyte solution, and thus the capacity and life characteristics of the lithium-sulfur battery can be improved.

An object of the present invention is to provide a novel sulfur-based positive electrode active material for a lithium-ion secondary battery which is excellent in cyclability and can largely improve a charging and discharging capacity, a positive electrode comprising the positive electrode active material and a lithium-ion secondary battery made using the positive electrode. The sulfur-based positive electrode active material is obtainable by subjecting a starting material comprising a polymer, sulfur and an organometallic compound dispersed in a form of fine particles to heat-treatment under a non-oxidizing atmosphere, wherein the particles of metallic sulfide resulting from sulfurization of the organometallic compound are dispersed in the heat-treated material, and particle size of the metallic sulfide particles is not less than 10 nm and less than 100 nm.