The present disclosure relates to an electrolyte solution for a lithium-sulfur secondary battery and a lithium-sulfur secondary battery comprising the same, more particularly to an electrolyte solution for a lithium-sulfur secondary battery containing a lithium salt and a non-aqueous solvent, wherein the non-aqueous solvent comprises an ether-based solvent and a nonsolvent, the ether-based solvent comprises a linear ether and a cyclic ether, and the nonsolvent comprises a compound having a specific structure.

An electrolyte solution for a lithium secondary battery includes an organic solvent, a lithium salt, and a fluorine-based additive in which a terminal difluoro-phosphite group (—OPF.sub.2) is bonded to a branched saturated hydrocarbon group. The fluorine-based additive prevent side reactions in the electrolyte solution to improve stability of a cathode active material.

A composition includes a first portion including Ni-rich LiNi.sub.xCo.sub.γMn.sub.zO.sub.2, where 0.5<x<1, 0<y<1, 0<z<1; a second portion including Li.sub.αZr.sub.βO.sub.γ, where 0<α<9, 0<β<3, and 1<γ<10 such that the second portion is coated on the first portion, and the first portion is doped with an elemental metal selected from at least one of Zr, Si, Sn, Nb, Ta, Al, and Fe. A method of forming a composition includes mixing a metal precursor with nickel-cobalt-manganese (NCM) precursor to form a first mixture; adding a lithium-based compound to the first mixture to form a second mixture; and calcining the second mixture at a predetermined temperature for a predetermined time to form the composition.

A method of preparing an electrochemical electrode which is partially or totally covered with a film that is obtained by spreading an aqueous solution comprising a water-soluble binder over the electrode and subsequently drying same. The production cost of the electrodes thus obtained is reduced and the surface porosity thereof is associated with desirable resistance values.

A secondary battery, and a battery module, a battery pack, and an electric apparatus containing the same are provided. The secondary battery includes: an electrolyte having a specific percentage of a low-viscosity solvent, a specific percentage of a high-dielectric-constant solvent, and a negative electrode having a negative electrode active material layer, and the secondary battery satisfies the relational expression:

[00001]$1\times {10}^{-4}4\le \frac{B\times C\times P}{ \mathrm{OI}\times \mathrm{CW}}\le 1\times {10}^{-3}$

where B is the percentage of the low-viscosity solvent in total solvent in the electrolyte by mass; C is a percentage of an electrolyte salt in the electrolyte by mass; P is a porosity of the negative electrode active material layer; CW is a coating weight of the negative electrode active material layer, measured in mg/cm.sup.2; and OI is an orientation index of the negative electrode active material layer.

A nonaqueous electrolyte includes a lithium salt and a nonaqueous solvent in which the lithium salt is dissolved. The nonaqueous solvent includes a fluorinated chain carboxylate ester and a dicarbonyl compound having two carbonyl groups in the molecule. The dicarbonyl compound is at least one selected from the group consisting of esters and acid anhydrides and has not more than three atoms between the two carbonyl groups.

An organic electrolytic solution includes a first lithium salt; an organic solvent; a bicyclic sulfate-based compound represented by Formula 1 below; and a nitrile group-containing compound, wherein the nitrile group-containing compound includes a plurality of nitrile groups:

##STR00001## in Formula 1, each of A.sub.1, A.sub.2, A.sub.3, and A.sub.4 is independently a covalent bond, a substituted or unsubstituted C.sub.1-C.sub.5 alkylene group, a carbonyl group, or a sulfinyl group, wherein both A.sub.1 and A.sub.2 are not a covalent bond and both A.sub.3 and A.sub.4 are not a covalent bond.

An organic electrolytic solution includes a first lithium salt; an organic solvent; a bicyclic sulfate-based compound represented by Formula 1 below; and a monocyclic phosphate-based compound represented by Formula K1 below:

##STR00001## wherein in Formula 1, each of A.sub.1, A.sub.2, A.sub.3, and A.sub.4 is independently a covalent bond, a substituted or unsubstituted C.sub.1-C.sub.5 alkylene group, a carbonyl group, or a sulfinyl group, wherein both A.sub.1 and A.sub.2 are not a covalent bond and both A.sub.3 and A.sub.4 are not a covalent bond, and in Formula K1, each of A.sub.5 and A.sub.6 is independently a substituted or unsubstituted C.sub.1-C.sub.5 alkylene group.

A lithium battery includes a cathode; an anode; and an organic electrolytic solution between the cathode and the anode, wherein the anode includes an anode current collector and an anode active material layer on the anode current collector, the anode active material layer includes carbonaceous and silicon-containing composite anode active materials, the anode active material layer includes first and second anode active material layers, and the first anode active material layer is between the anode current collector and the second anode active material layer, a content of silicon in the first anode active material layer is higher than the second anode active material layer, and the organic electrolytic solution includes a first lithium salt, an organic solvent, and a bicyclic sulfate-based compound represented by Formula 1 below:

##STR00001##

A lithium battery includes a cathode including a cathode active material; an anode including an anode active material; and an organic electrolytic solution between the cathode and the anode, wherein the anode active material includes a carbonaceous anode active material and a metallic anode active material, in an XRD spectrum of the anode, a peak intensity ratio (la/lb) of a peak intensity (la) of a carbonaceous anode active material oriented in a direction non-parallel to a surface of the anode to all peak intensities (lb) of the carbonaceous anode active material oriented in all directions is about 0.15 or more, and the organic electrolytic solution includes a first lithium salt, an organic solvent, and a bicyclic sulfate-based compound represented by Formula 1 below:

##STR00001##