An electrode binder of a lithium ion secondary battery comprising an aqueous dispersion of: (a) a polyvinylidene binder; (b) a (meth)acrylic polymer dispersant; (c) a crosslinking agent comprising an aminoplast and/or a polycarbodiimide; and (d) an organic diluent. The (meth)acrylic polymer dispersant is prepared from a mixture of monomers comprising one or more carboxylic acid group-containing (meth)acrylic monomers and one or more hydroxyl group-containing (meth)acrylic monomers, and carboxylic acid groups on the (meth)acrylic polymer dispersant are at least partially neutralized with a base. The binder can be used in the assembly of electrodes of lithium ion secondary batteries.

A lithium ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode has a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector. The negative electrode current collector satisfies:
(D2/D1)≥0.968  (1),
D2≥21.947*(X/100)−24.643  (2),
110≤X≤125  (3), and
where D1 is a first displacement amount in a first piercing test at a first piercing speed of 0.1 mm/min or more; D2 is a second displacement amount in a second piercing test at a second piercing speed of less than 0.1 mm/min; and X is an expansion coefficient (%) of the negative electrode active material layer.

A lithium electrode and a lithium secondary battery including the same. By using an olefin-based ion conducting polymer as a protective layer-forming material of a lithium electrode having a protective layer formed on a lithium metal layer, the lithium electrode may be protected from moisture or open air during a lithium electrode preparation process, lithium dendrite formation and growth from the lithium electrode may be prevented, and performance of a battery using the lithium electrode may be enhanced.

Provided are an all-solid-state battery and a preparation method thereof. The all-solid-state battery includes a positive electrode, a negative electrode, and a solid-state electrolyte located between the positive electrode and the negative electrode. The negative electrode includes a first negative electrode and a second negative electrode. The second negative electrode is located on a side of the first negative electrode. The solid-state electrolyte includes a first solid-state electrolyte and a second solid-state electrolyte. The first solid-state electrolyte is located between the positive electrode and the first negative electrode. The second solid-state electrolyte is located between the positive electrode and the second negative electrode. The roughness of the second solid-state electrolyte is greater than the roughness of the first solid-state electrolyte.

A solid electrolyte layer having a solid electrolyte and carbon, in which a dispersion degree (CV value) of the carbon measured by a quadrat method in a cross section of the solid electrolyte layer is more than zero and less than one.

Disclosed herein are a surface-treated copper foil for a negative electrode current collector for secondary batteries, a method for producing the same, and a negative electrode for secondary batteries including the same. The surface-treated copper foil includes needle-shaped copper particles formed on at least one surface thereof, wherein the copper particles have an average major-axis length of about 0.6 μm to about 2.0 μm and are separated from one another by a distance of about 1 μm to about 5 μm.

The present invention relates to a metal foil fatigue test apparatus and a metal foil fatigue test method using the same. The metal foil fatigue test apparatus includes: a metal foil moving unit including an unwinding roll, from which a metal foil is unwound, a plurality of guide rolls configured to support and transfer the metal foil supplied from the unwinding roll, and a rewinding roll where the metal foil transferred from the guide rolls is wound; and a tensile strength measuring unit configured to measure tensile strength of the metal foil.

A negative electrode for a lithium metal battery, a manufacturing method thereof, and a lithium metal battery comprising the same are provided. The negative electrode includes a metal current collector, a lithium metal layer formed on at least one surface of the metal current collector, and a protective layer formed on the lithium metal layer, the protective layer comprising a metal powder or metal wire, an alloyable metal powder or alloyable metal wire, or a mixture thereof.

An object of the present invention is to provide an aluminum foil and an aluminum member for electrodes having good adhesiveness to an electrode material and high conductivity with the electrode material. Provided is an aluminum foil having through holes including an aluminum oxide film having a thickness of 25 nm or less on a surface of the aluminum foil, and further a hydrophilic layer on a part of a surface of the aluminum oxide film.

A temperature sensor for a battery cell of a rechargeable battery is described, and includes a resistive sensing element, a first electrode, and a second electrode. The resistive sensing element, the first electrode, and the second electrode are affixed to a porous separator. The porous separator is interposed between an anode and a cathode of the battery cell. The resistive sensing element is electrically connected in series between the first electrode and the second electrode, and the resistive sensing element, the first electrode and the second electrode are affixed onto the separator as film layers, and are porous.