Semiconductor Energy Laboratory Co., Ltd.

Kai Kimura

Nobuhiro Inoue

Ryota Tajima

Kazutaka Kuriki

Teppei Oguni

Sachiko Kataniwa

Aya Uchida

Tamae Moriwaka

Shunpei Yamazaki

Junpei Momo

Kiyofumi Ogino

Tatsuya Ikenuma

Ai Nakagawa

Rika Yatabe

A power storage device with high capacity or high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode includes an active material, a first binder, and a second binder. The specific surface area of the active material is S [m/g]. The weight of the active material, the weight of the first binder, and the weight of the second binder are a, b, and c, respectively. The solution of {(b+c)/(a+b+c)}&#xd7;100&#xf7;S is 0.3 or more. The electrode includes a first film in contact with the active material. The first film preferably includes a region in contact with the active material. The first film preferably includes a region with a thickness of 2 nm or more and 20 nm or less. The first film contains a water-soluble polymer.

Electrode, power storage device, and electronic device

A decomposition reaction of an electrolyte solution and the like caused as a side reaction of charge and discharge is minimized in repeated charge and discharge of a lithium ion battery or a lithium ion capacitor, and thus the lithium ion battery or the lithium ion capacitor can have long-term cycle performance. A negative electrode for a power storage device includes a negative electrode current collector and a negative electrode active material layer which includes a plurality of particles of a negative electrode active material. Each of the particles of the negative electrode active material has an inorganic compound film containing a first inorganic compound on part of its surface. The negative electrode active material layer has a film in contact with an exposed part of the negative electrode active material and part of the inorganic compound film. The film contains an organic compound and a second inorganic compound.

Negative electrode for power storage device and power storage device

To improve the reliability of a power storage device. A granular active material including carbon is used, and a net-like structure is formed on part of a surface of the granular active material. In the net-like structure, a carbon atom included in the granular active material is bonded to a silicon atom or a metal atom through an oxygen atom. Formation of the net-like structure suppresses reductive decomposition of an electrolyte solution, leading to a reduction in irreversible capacity. A power storage device using the above active material has high cycle performance and high reliability.

Material for electrode of power storage device, power storage device, and electrical appliance

To provide a power storage device with a high capacity. To provide a power storage device with a high energy density. To provide a highly reliable power storage device. To provide a long-life power storage device. To provide an electrode with a high capacity. To provide an electrode with a high energy density. To provide a highly reliable electrode. To provide a long-life electrode. The power storage device includes a first electrode and a second electrode. The first electrode includes a first current collector and a first active material layer. The first active material layer includes a first active material and a first binder. The first active material is graphite. A separation strength F of the first electrode that is measured when the first active material layer is separated from the first current collector after the first electrode is immersed in a solution at a temperature higher than or equal to 20&#xb0; C. and lower than or equal to 70&#xb0; C. for longer than or equal to three hours is higher than or equal to 0.05 N/cm and lower than or equal to 5 N/cm per unit width of a sample that is separated.

A lithium-ion secondary battery with a high capacity retention rate is provided. In addition, a fabricating method of a lithium-ion secondary battery with a high capacity retention rate is provided. The lithium-ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution. The negative electrode includes a negative electrode active material layer. The electrolyte solution includes at least one of lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and lithium bis(fluorosulfonyl)amide (LiFSA). The electrolyte solution includes vinylene carbonate (VC). A coating film including lithium oxide is on a surface of the negative electrode active material layer. A fabricating method of a lithium-ion secondary battery includes a first step of enclosing a positive electrode, a negative electrode, and an electrolyte solution in an exterior body, and a second step of annealing the exterior body enclosing the positive electrode, the negative electrode, and the electrolyte solution for 24 hours or longer after the first step. The annealing in the second step is performed at a temperature higher than or equal to 80&#xb0; C. and lower than or equal to 100&#xb0; C.

Lithium-ion secondary battery, fabricating method therof, and electronic device

Irreversible capacity which causes a decrease in the charge and discharge capacity of a power storage device is reduced, and electrochemical decomposition of an electrolyte solution and the like on a surface of an electrode is inhibited. Further, the cycle characteristics of the power storage device is improved by reducing or inhibiting a decomposition reaction of the electrolyte solution and the like occurring as a side reaction in repeated charging and discharging of the power storage device. A power storage device electrode includes a current collector and an active material layer that is over the current collector and includes a binder and an active material. A coating film is provided on at least part of a surface of the active material. The coating film is spongy.

Power storage device electrode, method for forming the same, power storage device, and electrical device

An object is to improve the cycle performance by improving the reactivity between lithium and a negative electrode active material in the case where an alloy-based material such as silicon is used as the negative electrode active material. A method of manufacturing a lithium secondary battery including a positive electrode including a positive electrode active material into/from which lithium can be inserted/extracted, a negative electrode including a negative electrode active material into/from which lithium can be inserted/extracted, and an electrolyte solution is provided. The method includes the steps of electrochemically inserting lithium into the negative electrode with use of a counter electrode before the lithium secondary battery is assembled, electrochemically extracting part of the lithium inserted into the negative electrode after the insertion, and assembling the lithium secondary after the extraction.

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Kanagawa, Japan

Kai Kimura