Disclosed herein are a multilayer electrode and a lithium secondary battery including the same. The multilayer electrode includes an electrode current collector for transmitting electrons between an external wire and an electrode active material and three or more electrode mixture layers sequentially applied to the electrode current collector, wherein each of the electrode mixture layers includes an electrode active material and a conducting agent, and wherein the content of the conducting agent of one of adjacent electrode mixture layers that is relatively close to the current collector in the direction in which the electrode mixture layers are formed is higher than that of the conducting agent of the other of the adjacent electrode mixture layers that is relatively distant from the current collector.

A porous silicon composite including: a porous silicon composite cluster comprising a porous silicon composite secondary particle and a second carbon flake on at least one surface of the porous silicon composite secondary particle; and a carbonaceous layer on the porous silicon composite cluster, the carbonaceous layer comprising amorphous carbon, wherein the porous silicon composite secondary particle comprises an aggregate of two or more silicon primary particles, the two or more silicon primary particles comprise silicon, a silicon suboxide of the formula SiO.sub.x, wherein 0<x<2 on a surface of the silicon, and a first carbon flake on at least one surface of the silicon suboxide, the silicon suboxide is in a form of a film, a matrix, or a combination thereof, and the first carbon flake and the second carbon flake are each independently present in a form of a film, particles, a matrix, or a combination thereof. Also a method of preparing the porous silicon composite, a carbon composite, an electrode, and a device, each including the porous silicon composite, and a lithium battery including the electrode.

A porous silicon composite including: a porous silicon composite cluster comprising a porous silicon composite secondary particle and a second carbon flake on at least one surface of the porous silicon composite secondary particle; and a carbonaceous layer on the porous silicon composite cluster, the carbonaceous layer comprising amorphous carbon, wherein the porous silicon composite secondary particle comprises an aggregate of two or more silicon primary particles, the two or more silicon primary particles comprise silicon, a silicon suboxide of the formula SiO.sub.x, wherein 0<x<2 on a surface of the silicon, and a first carbon flake on at least one surface of the silicon suboxide, the silicon suboxide is in a form of a film, a matrix, or a combination thereof, and the first carbon flake and the second carbon flake are each independently present in a form of a film, particles, a matrix, or a combination thereof. Also a method of preparing the porous silicon composite, a carbon composite, an electrode, and a device, each including the porous silicon composite, and a lithium battery including the electrode.

Electrolytes and electrolyte additives for energy storage devices comprising functional thiophene compounds are disclosed. The energy storage device comprises a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte, and at least one electrolyte additive selected from a thiophene compound.

An energy storage device according to one aspect of the present invention includes: a negative electrode including a negative electrode substrate and a negative active material layer layered directly or indirectly on a surface of the negative electrode substrate; and a positive electrode. The negative active material layer contains a negative active material. The negative active material contains non-graphitizable carbon. In one direction of the negative electrode substrate, at least one end edge side of the negative active material layer is thicker than a central portion present between the one end edge side and the other end edge side facing the one end edge side. When a true density of the non-graphitizable carbon is A [g/cm.sup.3], an amount of charge B [mAh/g] of the negative electrode in a fully charged state satisfies the following formula 1.

[1]$-173\text{XA+1588}\le \text{B}\le \text{-830A+1800}$

The cathode material contains the active component, the conductive component and the connecting component. Organic biomaterial is used as the active component, acetylene carbon black is used as the conductive component and polyvinylidene fluoride is used as the connecting component.

An electrode material of a supercapacitor includes a negative material prepared by the following steps: first dispersing graphite oxide in deionized water; after stirring and ultrasonic treatment, reducing the graphite oxide into reduced graphene oxide by using a hydrazine hydrate, and vacuum drying at 40-80° C.; dispersing the reduced graphene oxide in a DMF solution with 2,6-diaminoanthraquinone, and stirring and performing the ultrasonic treatment again; at 60-90° C., adding isoamyl nitrite, and reacting for 18-24 h; and washing reaction products with ethanol and deionized water for multiple times, and finally freeze drying to obtain a product.

A purpose of the present invention is to provide a method for manufacturing, etc., a member for an electrochemical device in which the problem of irreversible change in the composition of the electrochemical device due to solvent depletion, moisture absorption, etc., during manufacturing of the electrochemical devices is unlikely to occur. This method for manufacturing a member for an electrochemical device includes performing at least one shaping operation described in the present specification on a shaping material composition that comprises: at least one filler (F); a plasticizer (P-S), being water, an ionic liquid, or a mixture thereof; and a polymer (P1), the shaping material composition being substantially free of an organic solvent and having plasticity and self-supporting property.

A novel electrode is provided. A novel power storage device is provided. A conductor having a sheet-like shape is provided. The conductor has a thickness of greater than or equal to 800 nm and less than or equal to 20 μm. The area of the conductor is greater than or equal to 25 mm.sup.2 and less than or equal to 10 m.sup.2. The conductor includes carbon and oxygen. The conductor includes carbon at a concentration of higher than 80 atomic % and oxygen at a concentration of higher than or equal to 2 atomic % and lower than or equal to 20 atomic %.

A novel electrode is provided. A novel power storage device is provided. A conductor having a sheet-like shape is provided. The conductor has a thickness of greater than or equal to 800 nm and less than or equal to 20 μm. The area of the conductor is greater than or equal to 25 mm.sup.2 and less than or equal to 10 m.sup.2. The conductor includes carbon and oxygen. The conductor includes carbon at a concentration of higher than 80 atomic % and oxygen at a concentration of higher than or equal to 2 atomic % and lower than or equal to 20 atomic %.