Negative electrode active material for lithium secondary battery and method for manufacturing same

Abstract

This negative electrode material for a lithium secondary battery is formed from a powder formed by carrying out in order a step for creating an etched foil by etching both surfaces of a foil that has a Fe content of 0.05% by mass or less and Al as a main component and a step for cutting that etched foil. This powder includes particles (1) that have holes (2) that are opened in the surface of the particles and have a hole diameter of 0.5 [mu]m or greater. The total of the opening surface area for all of the holes (2) in the surface of a particle (1) in the particles (1) having the holes (2) is 10% or greater of the surface area of the particle having the holes (2). With the use of this negative electrode material (1) for a lithium secondary battery, increased life for cycle life of the lithium secondary battery can be achieved.

Description

technical field [0001] The present invention relates to a negative electrode active material for a lithium secondary battery and a manufacturing method thereof, and more specifically, to a negative electrode active material for a nonaqueous electrolyte secondary battery capable of absorbing / releasing Li ions in a large amount and reversibly, and a manufacturing method thereof. Here, the nonaqueous electrolyte secondary battery includes a secondary battery using a nonaqueous electrolyte obtained by dissolving an electrolyte in an organic solvent, and a secondary battery using a nonaqueous electrolyte such as a polymer electrolyte or a colloidal electrolyte. Background technique [0002] Lithium secondary batteries, such as lithium ion batteries and lithium polymer batteries, have high energy density and are being used not only as main power sources for mobile communication devices and portable electronic devices, but also as power sources for large-scale power storage and vehi...

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Problems solved by technology

[0004] On the other hand, it is known that a high theoretical specific capacity can be obtained when a negative electrode formed of metal Li is used in a lithium secondary battery, but there is a big disadvantage that the metal Li forms a dendrite in the negative electrode during charging. Form precipitation, and continue to grow due to repeated charge and discharge, and finally reach the positive side to cause an internal short circuit

[0009] However, in the negative electrode formed of the negative electrode active material described in Patent Document 1 and Patent Document 2, although a large initial discharge specific capacity can be obtained, it cannot effectively suppress the expansion / shrinkage of the negative electrode caused by repeated charging and discharging. Cracking or micronization of the negative electrode caused by expansion / shrinkage makes it impossible to achieve a longer cycle life

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