Semiconductor Energy Laboratory Co., Ltd.

Aya Uchida

Teppei Oguni

Kazutaka Kuriki

Kai Kimura

Masahiro Takahashi

Yohei Momma

Teruaki Ochiai

Mayumi Mikami

Yumiko Yoneda

Jun Ishikawa

Kazuhei Narita

Rie Yokoi

A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

Positive electrode active material, method for manufacturing positive electrode active material, and secondary battery

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 power storage device with high capacity is provided. Alternatively, a power storage device with high energy density is provided. Alternatively, a highly reliable power storage device is provided. Alternatively, a long-life power storage device is provided. A power storage device is characterized by comprising a separator, a first electrode, a second electrode, an electrolytic solution, in which the separator is provided between the first electrode and the second electrode, the first electrode includes an active material layer and a current collector, the first electrode includes a pair of coating films between which the current collector is sandwiched, the active material layer includes a region in contact with the current collector, the active material layer includes a region in contact with at least one of the pair of coating films, and the electrolytic solution includes an alkali metal salt and an ionic liquid.

Power storage device and electronic device

When cellulose is used as a separator, the cellulose is impregnated with an ionic liquid. Charge and discharge are repeated with this separator touching a surface of a current collector; then, the separator is changed in color. Thus, it is an object to provide a power storage device with a structure in which a side reaction other than a battery reaction, e.g., a change in color of separator, is unlikely to occur. In the power storage device, a separator impregnated with an ionic liquid is not in contact with a surface of a current collector. The separator has a tubular shape, a bag-like shape, or a sheet-like shape. The separator includes cellulose. The power storage device including the ionic liquid is non-volatile and non-flammable. The power storage device can be bent.

Power storage device including separator surrounding electrode

A power storage device with high capacity, a power storage device with high energy density, a highly reliable power storage device, and a long-life power storage device are provided. The power storage device includes a positive electrode, a separator, a negative electrode, and an electrolytic solution. The electrolytic solution contains an alkali metal salt and an ionic liquid. The separator is located between the positive electrode and the negative electrode. At least part of the positive electrode overlaps with the negative electrode. At least part of an end portion of the negative electrode is located inside a region between end portions of the positive electrode.

Growing community of inventors

Kanagawa, Japan

Aya Uchida