A negative electrode active material including a core, an intermediate layer on a surface of the core, and a shell layer on a surface of the intermediate layer, wherein the core includes a silicon oxide of SiO.sub.x (0<x<2); the intermediate layer includes a lithium silicate, the shell layer includes lithium fluoride (LiF) and the intermediate layer is present in an amount of 5 wt %-15 wt % based on a total weight of the negative electrode active material. Also, a method for preparing the negative electrode active material, and a negative electrode and lithium secondary battery including the same. The negative electrode active material provides excellent initial efficiency and life characteristics.

The present disclosure relates to a method of making core-shell and yolk-shell nanoparticles, and to electrodes comprising the same. The core-shell and yolk-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells, such as fluoride shuttle batteries. The shell may protect the metal core from oxidation, including in an electrochemical cell. In some embodiments, an electrochemically active structure includes a dimensionally changeable active material forming a particle that expands or contracts upon reaction with or release of fluoride ions. One or more particles are at least partially surrounded with a fluoride-conducting encapsulant and optionally one or more voids are formed between the active material and the encapsulant using sacrificial layers or selective etching. When the electrochemically active structures are used in secondary batteries, the presence of voids can accommodate dimensional changes of the active material.

A negative electrode active material including a core, an intermediate layer on a surface of the core, and a shell layer on a surface of the intermediate layer, wherein the core includes a silicon oxide of SiO.sub.x (0<x<2); the intermediate layer includes a lithium silicate, the shell layer includes lithium fluoride (LiF) and the intermediate layer is present in an amount of 5 wt %-15 wt % based on a total weight of the negative electrode active material. Also, a method for preparing the negative electrode active material, and a negative electrode and lithium secondary battery including the same. The negative electrode active material provides excellent initial efficiency and life characteristics.

Redox flow battery performance may be improved with a metal containing ionic liquid as a liquid electrolyte. Metal containing ionic liquids are liquids at all temperatures of interest and therefore do not need dilution. As such, voltage separation between the anolyte and catholyte may exceed 0.5 V and therefor rival current state-of-the-art energy storage technologies and with higher voltage separation may attain energy densities above 100 Wh/L.

A solid-state ion conductor including a compound of Formula 1:

Li.sub.1+(4-a)yA.sup.a.sub.yM.sub.1-yXO.sub.5   Formula 1

wherein, in Formula 1, A is an element of Groups 1 to 3 or 11 to 13, or a combination thereof, wherein an oxidation state a of A is 1≤a≤3, M is an element having an oxidation state of +4 of Groups 4 or 14, or a combination thereof, X is an element having an oxidation state of +5 of Groups 5, 15, 17, or a combination thereof, and 0<y≤1.

A solid electrolyte material comprises Li, T, X and A wherein T is at least one of Sb, P, As, Si, Ge, Al, and B; X is one or more halogens or N; A is one or more of S or Se. The solid electrolyte material has peaks at 2θ=14.5°±0.50°, 16.8°±0.50°, 23.9°±0.50°, 28.1°±0.50°, and 32.5°±0.50 in X-ray diffraction measurement with Cu-Kα(1,2)=1.54064 Å and may include glass ceramic and/or mixed crystalline phases.

Disclosed herein are batteries comprising cathodes having halogenated compounds as cathode active materials and including a greenhouse gas within the battery. The halogenated batteries can be operated under an atmosphere comprising a greenhouse gas, wherein the battery is fabricated under a greenhouse gas atmosphere, or wherein the greenhouse gas is introduced into the battery before use. Also disclosed herein are methods of fabricating batteries comprising cathodes having halogenated compounds as cathode active materials and including a greenhouse gas within the battery. The halogenated batteries can include an aliphatic nitrile compound as part of the electrolyte, an organic material having a conjugated cyclic structure as part of the cathode active material, or a metal oxide as part of the anode active material to improve the battery performance.

According to one embodiment, a secondary battery includes a positive electrode, a negative electrode, a nonaqueous electrolyte and a separator. The positive electrode includes a halide including at least one metal element selected from the group consisting of copper, iron, nickel, cobalt, tin, and zinc. The negative electrode includes at least one selected from the group consisting of lithium metal, a lithium alloy, and a compound capable of having Li inserted and extracted. The nonaqueous electrolyte includes an ionic liquid including chlorine ions. The separator has lithium ion conductivity, and is interposed between the positive electrode and the negative electrode.

The present disclosure provides a composite wherein NaCl nanoparticles are uniformly dispersed on reduced graphene oxide (rGO), a positive electrode active material including the same, a sodium secondary battery including the same, and a method for preparing the same. The positive electrode active material according to the present disclosure has a structure wherein NaCl nanoparticles are uniformly dispersed on rGO in a one-step process through chemical self-assembly. Therefore, the positive electrode active material according to the present disclosure exhibits superior electrochemical properties with high capacity because the small NaCl particles are dispersed uniformly and is economically favorable because the preparation process is simple.

The present disclosure relates to a cathode active material for a secondary battery, a cathode for a secondary battery including the same, a secondary battery including the cathode for a secondary battery and manufacturing methods thereof. More particularly, it is possible to obtain a secondary battery having excellent electrochemical characteristics by electrochemically inducing a structural phase change in the cathode active material of a secondary battery including NaCl as a cathode active material.