A lithium secondary battery comprising a cathode, an anode, an elastic polymer protective layer disposed between the cathode and the anode, and a working electrolyte, wherein the elastic polymer protective layer comprises a high-elasticity polymer having a thickness from 2 nm to 100 μm, a lithium ion conductivity from 10.sup.−8 S/cm to 5×10.sup.−2 S/cm at room temperature, and a fully recoverable tensile elastic strain from 2% to 1,000% when measured without any additive dispersed therein and wherein the high-elasticity polymer comprises at least a crosslinked polymer network of chains from at least one polymer containing carboxylic and/or hydroxyl groups or from at least one polymer that is water-soluble prior to crosslinking.

A separator for alkaline batteries, which exhibits excellent strength, dimensional stability and chemical stability in an electrolyte solution, while having high shielding properties, high liquid holding properties and low resistance. A separator for alkaline batteries, which is used for the purpose of separating a positive electrode active material and a negative electrode active material from each other, and holding an electrolyte solution, and which is obtained by stacking and integrating a fiber layer A that has a density of 0.52-0.62 g/cm.sup.3 and a thickness of 25-35 μm and a fiber layer B that has a density of 0.40-0.50 g/cm.sup.3 and a thickness of 25-35 μm, so that the entirety of the separator has a density of 0.45-0.57 g/cm.sup.3 and a thickness of 50-70 μm.

According to one embodiment, there is provided a nonaqueous electrolyte battery including a positive electrode, a negative electrode, a nonaqueous electrolyte and a separator. The positive electrode includes a positive electrode active material containing Li.sub.xNi.sub.1-a-bCo.sub.aMn.sub.bM.sub.cO.sub.2 (0.9<x≤1.25, 0<a≤0.4, 0≤b≤0.45, 0≤c≤0.1, and M represents at least one element selected from the group consisting of Mg, Al, Si, Ti, Zn, Zr, Ca, and Sn). The separator includes polyester. A pore volume in a pore size distribution according to a mercury intrusion porosimetry is in a range of 0.9 cm.sup.3/g to 3 cm.sup.3/g. An air permeability value according to a Gurley method is in a range of 2 sec/100 ml to 15 sec/100 ml.

To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.

The invention relates to the use of a lyocell fiber (1) for the manufacture of a nonwoven fiber fleece (10, 100). To manufacture a thin nonwoven fiber fleece with sufficient mechanical properties, the use of a lyocell fiber is proposed, where the fiber (1) has a cross-sectional aspect ratio of at least 1.8.

The invention further relates to a nonwoven fiber fleece (10, 100). In order to manufacture a thin nonwoven fiber fleece (10, 100) suitable for use as a battery separator, it is proposed, that the fiber fleece comprises at least two layers (11, 12) of fibrillated lyocell fibers (13), with the fibrillated lyocell fibers (13) having solid cores (14, 110) and fibrils (15) protruding from said cores (14), the fibers and fibrils (15) being intermingled to form the fiber fleece (10), embedding the solid cores (14) therein, whereby the solid cores (14, 110) of the fibrillated lyocell fibers (13) have an average cross-sectional aspect ratio k of at least 1.5.

A coating solution for lithium ion battery separators which comprises inorganic particles, an organic polymer binder and carboxymethyl cellulose having an etherification rate of 1.10 to 2.00 or a salt thereof, or a coating solution for lithium ion battery separators comprising inorganic particles containing magnesium hydroxide having a linseed oil absorption of 30 to 80 (g/100 g), and a separator having a coating layer formed from the coating solution on a substrate and high safety and low internal resistance.

A polyolefin micro porous film includes at least one of polyethylene and polypropylene, in which the compressive elastic modulus is 95 MPa or more and 150 MPa or less, the surface roughness (Ra) of a film surface is measured for a front surface and a rear surface, and the average value (Ra(ave)) thereof is 0.01 μm to 0.30 μm.

The present invention provides a porous membrane for water treatment, comprising: a high molecular weight polyethylene, a water-soluble polymer and an antioxidant, the high molecular weight polyethylene having an average molecular weight of 1.0×10.sup.5 to 10.0×10.sup.6 and a density of 0.940 to 0.976 g/cm.sup.3; wherein, the weight of the water-soluble polymer is 5 to 50 parts, the weight of the antioxidant is 0.1 to 10 parts, based on 100 parts of the weight of the high molecular weight polyethylene. The porous membrane for water treatment prepared by the present invention has a thickness of 5 to 30 μm, a pore size of 10 to 100 nm, a porosity of 20 to 60%, and a surface contact angle of 30° to 95°. The porous membrane according to the present invention has good durability, simple preparation process, and relatively thin thickness, a uniform pore size distribution and small pore size, good hydrophilicity, as well as good filtration and adsorption effect.

The present invention provides a magnesium anode and an electrochemical cell comprising the anode.

The present invention relates to a separator for a secondary battery and a lithium secondary battery including the separator, the separator including: a porous substrate and a heat-resistant layer disposed on at least one surface of the porous substrate, wherein the heat-resistant layer includes an acrylic heat-resistant binder, an adhering binder, and a filler, the acrylic heat-resistant binder including a structural unit derived from (meth)acrylate or (meth)acrylic acid, a cyano group-containing structural unit, and a sulfonate group-containing structural unit, the adhering binder includes a structural unit including a structural unit including hydroxyl group, a structural unit including an acetate group, and a structural unit including an alkali metal.