A positive electrode active material for lithium secondary batteries includes a lithium composite metal compound containing secondary particles that are aggregates of primary particles which are capable of being doped or dedoped with lithium ions and satisfies all of specific requirements (1) to (4).

A binder solution for manufacturing silicon-based anodes useful for lithium-ion electrochemical cells is described herein. The binder solution comprises a poly(carboxylic acid) binder dissolved in a mixed solvent system comprising an amide solvent of Formula I, as described herein, and a second solvent which can be water and/or an organic solvent. The binder preferably comprises poly(acrylic acid). The mixed solvent system comprises about 10 to about 99 vol % of the amide solvent of Formula I. The binder solution is utilized as a solvent for a slurry of silicon-containing particles for preparing a silicon-containing electrode. The slurries made with the mixed solvent systems have higher viscosity and are more stable than slurries containing the same concentrations of silicon particle, carbon particles, and binder in water as the sole solvent.

An object of the present invention is to provide a composite material usable as a negative electrode material of a lithium-ion secondary battery.

A composite material of the present invention includes: a carbonaceous material; and a metal oxide layer coating a surface of the carbonaceous material, in which the metal oxide layer coats the surface of the carbonaceous material, forming a sea-island structure in which the metal oxide layer is scattered in islands, and a coating rate of the carbonaceous material with the metal oxide layer is 20% or more and 80% or less.

A composite material of the present invention includes: a carbonaceous material; and a metal oxide layer and amorphous carbon layer coating the surface of the carbonaceous material, in which the metal oxide layer is scattered in islands on the surface of the carbonaceous material.

A composite material of the present invention includes: a carbonaceous material; and a metal oxide layer coating the surface of the carbonaceous material, in which the metal oxide layer has at least a portion having a thickness of more than 10 nm, and in a coated area with the metal oxide, an area percentage of a portion having a thickness of 10 nm or less is 70% or more and 99% or less, and an area percentage of the portion having a thickness of more than 10 nm is 1% or more and 30% or less. A composite material of the present invention also includes: a carbonaceous material; and a metal oxide layer and amorphous carbon layer coating the surface of the carbonaceous material, in which the metal oxide layer has at least a portion having a thickness of more than 10 nm, and in a coated area with the metal oxide layer, an area percentage of a portion having a thickness of 10 nm or less is 30% or more and 70% or less, and an area percentage of the portion having a thickness of more than 10 nm is 30% or more and 70% or less.

Provided is a negative electrode active material for a lithium secondary battery including: a silicon oxide (SiO.sub.x, 0<x≤2) composite including an alkali metal or alkaline earth metal-containing phosphate; and an aluminum-containing phosphate.

The negative electrode disclosed herein includes: a negative electrode current collector; and a negative electrode active material layer formed on the surface of the negative electrode current collector. The negative electrode active material layer contains silicon oxide containing at least one alkali earth metal. The negative electrode active material layer includes at least a first layer and a second layer. The first layer is disposed between the second layer and the negative electrode current collector. The second layer contains 2 mass % or less of the silicon oxide containing the alkali earth metal, relative to 100 mass % of the negative electrode active material in the second layer. The amount of the alkali earth metal in the first layer calculated based on energy dispersive X-ray spectroscopy using a scanning electron microscope image is higher than the amount of the alkali earth metal in the second layer.

An energy storage device can include a first electrode, a second electrode and a separator between the first electrode and the second electrode wherein the first electrode or the second electrode includes elemental lithium metal and carbon particles. A method for fabricating an energy storage device can include forming a first electrode and a second electrode, and inserting a separator between the first electrode and the second electrode, where forming the first electrode or the second electrode can include combining elemental lithium metal and a plurality of carbon particles.

According to one embodiment, provided is a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes lithium manganese composite oxide particles having a spinel crystal structure and lithium cobalt composite oxide particles. The negative electrode includes a titanium-containing oxide. The nonaqueous electrolyte contains a propionate ester. The battery satisfies 0.8≤p/n≤1.2 and 1≤w/s≤60. p denotes a capacity per unit area of the positive electrode. n denotes a capacity per unit area of the negative electrode. w denotes a content of the propionate ester in the nonaqueous electrolyte and is in a range of 10% by weight to 60% by weight. s denotes an average particle size of the lithium manganese composite oxide particles.

A lithium battery including: a cathode; an anode; and an electrolyte between the cathode and the anode, wherein the cathode includes a cathode active material represented by Formula 1,
Li.sub.xNi.sub.yM.sub.1−yO.sub.2-zA.sub.z  Formula 1 wherein 0.95≤x≤1.2, 0.75≤y≤0.98, and 0≤z<0.2, M is Al, Mg, Mn, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Bi, or a combination thereof, and A is an element having an oxidation number of −1, −2, or −3, wherein each element of M is independently present in an amount of 0.02≤y≤0.3, wherein a total content of M is 0.02≤y≤0.3;
and wherein the electrolyte includes a lithium salt, a non-aqueous solvent, and a diallyl compound represented by Formula 2, ##STR00001## wherein L.sub.1 and L.sub.2 are each independently a single bond, a C.sub.1-C.sub.20 alkylene group, or a substituted or unsubstituted C.sub.2-C.sub.20 alkenylene group.

A lithium-sulfur battery cathode including conductive porous carbon particles vacuum infused with sulfur and a conductive collector substrate to which the sulfur infused porous carbon particles are deposited. The sulfur infused carbon particles are encapsulated by an encapsulation polymer, the encapsulation polymer having ionic conductivity, electronic conductivity, polysulfide affinity, or combinations thereof. A lithium-sulfur battery including the lithium-sulfur battery cathode, a lithium anode and an electrolyte disposed between the sulfur cathode and the lithium anode is also provided. Methods of producing the sulfur cathode for use in a lithium-sulfur battery by a hybrid vacuum-and-melt method are also provided.

An electrolyte solution additive, a non-aqueous electrolyte solution including the same, and a lithium secondary battery including the same are disclosed herein. In some embodiments, an electrolyte solution additive is represented by Formula 1

##STR00001##

wherein, in Formula 1,

R is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms.