A liquid composition includes particles and a solvent, wherein a contact angle of the liquid composition with respect to a substrate is greater than a contact angle of the solvent with respect to the substrate, and the contact angle of the substrate with respect to water observed 9 seconds after the substrate comes into contact with the water is 45 degrees to 75 degrees.

Disclosed is a functional layer for an electrochemical device that comprises inorganic particles and a particulate polymer, wherein the functional layer comprises a particle-detached portion, in a plan view of a surface of the functional layer, a ratio of an area of the particle-detached portion in a total area of the particulate polymer and the particle-detached portion is 0.1% or more and 40.0% or less, and a volume-average particle diameter of the particulate polymer is larger than a thickness of an inorganic particle layer comprising the inorganic particles.

Disclosed is a functional layer for an electrochemical device that comprises inorganic particles and a particulate polymer, wherein the functional layer comprises a particle-detached portion, in a plan view of a surface of the functional layer, a ratio of an area of the particle-detached portion in a total area of the particulate polymer and the particle-detached portion is 0.1% or more and 40.0% or less, and a volume-average particle diameter of the particulate polymer is larger than a thickness of an inorganic particle layer comprising the inorganic particles.

A slurry composition for coating a secondary battery separator, a separator prepared using the same, and a secondary battery including the separator, wherein the slurry composition includes a phenolic compound including two or more aromatic rings, inorganic particles, a binder, and a solvent.

A flame-resistant polymer composite separator for use in a lithium battery, wherein the polymer composite separator comprises (a) a binder or matrix polymer; (b) 0.1% to 50% by weight of a lithium salt dispersed in the polymer; and (c) from 30% to 99% by weight of particles or fibers of an inorganic material or polymer fibers that are dispersed in or bonded by the polymer, wherein the polymer is a polymerization or crosslinking product of a reactive additive comprising (i) a first liquid solvent that is polymerizable, (ii) an initiator or crosslinking agent, and (iii) the lithium salt and wherein the polymer composite separator has a thickness from 50 nm to 100 μm and a lithium ion conductivity from 10.sup.−8 S/cm to 5×10.sup.−2 S/cm at room temperature.

A separator for an electrochemical device having a low content of secondary particles formed by aggregation of inorganic particles in the inorganic coating layer. The separator has a low content of secondary particles protruding from the separator surface to a predetermined height. Since the inorganic particles are not aggregated but are distributed homogeneously in the inorganic coating layer, the separator has uniform dispersion of pressure over the whole surface of the separator, when it is applied to a battery and pressure is generated in the battery due to the charge/discharge of the battery. Deformation of the separator is minimized. When using a porous film as a separator substrate, there is a low tendency for intensive application of pressure from the secondary particles to a local site of the separator substrate, and thus the separator substrate is less damaged and the possibility of short-circuit generation is reduced.

A method of manufacturing a lithium secondary battery, which includes coating a slurry for forming a porous coating layer on a porous polymer substrate and drying the porous coating layer under a humidified condition to form a preliminary separator; forming an electrode assembly, wherein the preliminary separator is interposed between a positive electrode and a negative electrode, placing the electrode assembly into a battery case and injecting an electrolytic solution into the battery case; and thermally treating the electrode assembly. A lithium secondary battery manufactured by the method is also provided. Accordingly, the separator has significantly improved ionic conductivity compared to separators commonly used in the art.

Disclosed is a separator including inorganic particles and a binder resin. The separator may be used as a free standing type separator including no separator substrate, such as a polymer resin film, and thus causes no problem of heat shrinking. In addition, the separator includes an elastomer to provide a small change in dimension and high elongation, and thus is prevented from being damaged by external impact.

A lithium secondary battery comprising a cathode, an anode, and a thermally stable polymer composite separator disposed between the cathode and the anode, wherein the polymer composite separator comprises (i) a thermally stable polymer; (ii) from 0.1% to 30% by weight of a lithium salt dispersed in the thermally stable polymer; and (iii) from 30% to 99% by weight of particles of an inorganic material wherein the inorganic material particles are dispersed in or bonded by the thermally stable polymer and the composite separator has a thickness from 50 nm to 100 μm and a lithium ion conductivity from 10.sup.−8 S/cm to 5×10.sup.−2 S/cm at room temperature. Also provided are the thermally stable and ion-conducting polymer composite separators and a process for producing such a separator.

A lithium secondary battery comprising a cathode, an anode, and a thermally stable polymer composite separator disposed between the cathode and the anode, wherein the polymer composite separator comprises (i) a thermally stable polymer; (ii) from 0.1% to 30% by weight of a lithium salt dispersed in the thermally stable polymer; and (iii) from 30% to 99% by weight of particles of an inorganic material wherein the inorganic material particles are dispersed in or bonded by the thermally stable polymer and the composite separator has a thickness from 50 nm to 100 μm and a lithium ion conductivity from 10.sup.−8 S/cm to 5×10.sup.−2 S/cm at room temperature. Also provided are the thermally stable and ion-conducting polymer composite separators and a process for producing such a separator.