SK IE Technology Co., Ltd.

Provided is a polyamideimide film and a window cover film including the same. More particularly, a polyamideimide film which may provide physical properties satisfying both modulus and retardation in a thickness direction which are in a trade-off relationship with each other, and thus, has a less screen distortion phenomenon when it is applied to a window cover film and excellent optical properties, and a window cover film including the same are provided.

Composite separators and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator include: a porous substrate; and a ceramic layer disposed on at least one surface of the substrate, the ceramic layer including inorganic particles and a binder, wherein the inorganic particles have an average particle diameter (D50) in a range of 0.20 μm to 0.40 μm and a ratio (A/B) of at least of 1.05, the ratio (A/B) being calculated between an area (A) on a small particle diameter side and an area (B) on a large particle diameter side based on a maximum peak in a particle size distribution diagram of the inorganic particles. The composite separator may exhibit excellent mechanical and thermal stability and excellent ion conduction properties.

Composite separators and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator includes: a porous substrate; and a coating layer disposed on at least one surface of the substrate and including organic particles, wherein the coating layer satisfies the following Equation 1, and the composite separator exhibits excellent heat resistance, adhesive strength, and fusion strength with an electrode even at a small thickness, while suppressing a blocking phenomenon: 4 , 000 ≤ ( A × D 2 ) / T ≤ 5 , 500 [ Equation ⁢ 1 ] wherein A, D, and T are as defined in the specification.

Composite separators, methods for manufacturing the composite separators, and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator includes a porous substrate, and a ceramic layer formed on at least one surface of the substrate. The ceramic layer includes inorganic particles, a binder that includes carboxymethyl cellulose and polyacrylamide, and a particulate fusing agent. The ceramic layer satisfies the following Equation 1. 0.9 < T × ( W ⁢ 1 + W ⁢ 2 ) W ⁢ 2 × D < 2 . 4 [ Equation ⁢ 1 ] wherein T, W1, W2, and D are as defined in the specification. The composite separator may secure excellent heat resistance, adhesive strength, and fusion strength with an electrode.

Separator and electrochemical devices including separators are disclosed. In an embodiment, a separator includes: a substrate; an inorganic particle layer formed on at least one surface of the substrate; and an adhesive layer formed on the inorganic particle layer, wherein an adhesive strength Fx) is defined as a force measured between a probe and a surface of the separator at a stage temperature of x° C. using an atomic force microscope (AFM) equipped with the probe having a spring constant of 40 N/m, an average radius of 8 nm, and a scanning speed of 0.5 Hz, wherein F40 is in a range of 1 nN to 30 nN, and wherein the separator satisfies the following Formula 1: F75/F40≥5.

Composite separators, methods for manufacturing the composite separators, and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator includes a porous substrate, and a ceramic layer disposed on at least one surface of the substrate and including inorganic particles and a binder, wherein the binder includes carboxymethyl cellulose having a weight-average molecular weight in a range of 180,000 to 280,000 g/mol and a degree of substitution in a range of 0.6 to 1.2. The composite separator may exhibit excellent mechanical and thermal stability and ion conduction properties.

Composite separators, methods for manufacturing the composite separators, and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator includes a porous substrate, and a ceramic layer disposed on at least one surface of the substrate and including inorganic particles and a binder, wherein the binder includes polyacrylamide and carboxymethyl cellulose having a weight-average molecular weight of at least 180,000 g/mol and a degree of substitution in a range of 0.6 to 1.2, the polyacrylamide and carboxymethyl cellulose being included at a weight ratio of 60 to 90:40 to 10. The composite separator may exhibit excellent mechanical and thermal stability and excellent ion conduction properties.

Composite separators, methods for manufacturing the composite separators, and electrochemical devices including the composite separators are disclosed. In an embodiment, a composite separator includes: a porous substrate; and a ceramic layer formed on at least one surface of the substrate. Specifically, the ceramic layer includes inorganic particles, a binder, and a particulate fusing agent and satisfies the following Equation 1, and the binder is carboxymethyl cellulose having a weight average molecular weight of 180,000 g/mol to 280,000 g/mol. The composite separator based on the disclosed technology may secure excellent heat resistance, adhesive strength, and fusion strength with an electrode: 0.9 < T × ( W ⁢ 1 + W ⁢ 2 ) W ⁢ 2 × D < 2.4 [ Equation ⁢ 1 ] wherein T, W1, W2, and D are as defined in the specification.

Provided are a polyethylene microporous membrane, a method for manufacturing the same, and a separator including the microporous membrane. According to an embodiment of the present disclosure, a microporous membrane is provided which includes a polyethylene having a weight average molecular weight of 1×10 5 g/mol to 10×10 5 g/mol, and has a thickness of 3 μm to 20 μm, a puncture strength of 0.25 N/μm or more, a gas permeability of 1.5×10 −5 Darcy or more, a shrinkage rate in the transverse direction of 10% or less as measured after being allowed to stand at 131° C. for 1 hour, a tensile strength in the machine direction of 1500 kg/cm 2 or more, a tensile strength in the transverse direction of 2000 kg/cm 2 or more, and a ratio between the tensile strength in the machine direction and the tensile strength in the transverse direction of 0.5 to 0.7.

Provided are a polyolefin-based microporous membrane and methods for manufacturing the same, a separator comprising the polyolefin-based microporous membrane, and a secondary battery comprising the separator. The polyolefin-based microporous membrane or the separator comprising the same comprises a polyolefin, and has a gas permeability of about 2.5×10 −5 Darcy or more, a shrinkage rate in the transverse direction (TD) at 120° C. of about 10% or less, and a BDV index of about 15 or more as represented by the following Equation 1: BDV ⁢ index ⁢ = ( ( P 2 + M 4 ) D × d × ε ) × 1 ⁢ 0 ⁢ 0 [ Equation ⁢ 1 ] wherein the variables are defined as follows: P: puncture strength (N/μm) of the polyolefin-based microporous membrane; M: viscosity average molecular weight (×10 5 g/mol) of polyolefin; D: gas permeability (× 10 −5 Darcy) of the polyolefin-based microporous membrane; d: average pore size (nm) of the polyolefin-based microporous membrane; and ε: porosity of the polyolefin-based microporous membrane.)