Electrode for electrochemical elment, process for producing the electrode, and electrochemical element using the electrode

Abstract

Having a current collector having a concave portion and a convex portion at least on one side, and a columnar body formed on the convex portion of the current collector, the columnar body contains an active material for inserting and extracting lithium ions bonding at least with oxygen, and the oxygen content ratio of the active material of the columnar body becomes smaller as going away from the interface of the current collector.

Description

technical field [0001] The present invention relates to an electrochemical element having excellent charge-discharge characteristics, and more specifically, to an electrode for an electrochemical element having an excellent capacity retention rate, a method for producing the same, and an electrochemical element using the electrode for an electrochemical element. Background technique [0002] Recently, as an electrochemical element, for example, a lithium ion secondary battery representing a nonaqueous electrolyte secondary battery has been widely used because of its light weight, high electromotive force, and high energy density. For example, demand for lithium-ion secondary batteries is expanding as a power source for driving various types of portable electronic devices and mobile communication devices such as mobile phones, digital cameras, video cameras, and notebook computers. [0003] The composition of the lithium-ion secondary battery includes: a positive electrode co...

AI Technical Summary

Problems solved by technology

As a result, if compared with the case where it is formed on the entire surface, its influence will be suppressed, but there is still a problem that peeling and the like will occur under the action of stress that is also generated at the interface between the columnar thin film and the current collector. Dramatic improvement in cycle characteristics cannot be expected

In addition, although the tip of the active material layer swells, the active material layer near the interface of the current collector is difficult to swell, so there is a problem of cracking and peeling of the active material layer as the charge-discharge cycle progresses.

In particular, when the thickness of the active material layer becomes thicker, this influence becomes significant, and there is also a problem of coping with high capacity.

In addition, Patent Document 3 also describes that unevenness is provided on the surface of the current collector, and an active material layer having unevenness is formed along the unevenness, but essentially the same problem as above exists.

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