Composites comprising an exfoliated graphite support material having a degree of graphitization g in an range of 50 to 93%, obtained by XRD Rietveld analysis, which is coated with ZnO nanoparticles. These composites are produced by three different methods: A) (syn) the method comprises the following consecutive steps: i) a Zn(II)salt is dissolved in a solvent ii) graphite and a base are added simultaneously iii) the mixture is stirred under impact of ultrasound iv) the solvent is removed from the suspension or B) (pre) the method comprises the following consecutive steps: i) graphite is suspended in a solvent and exfoliated via impact of ultrasound ii) a Zn(II)salt and a base are added simultaneously forming nano-ZnO particles iii) the mixture is stirred iv) the solvent is removed from the suspension or C) (post) the method comprises the following steps: i) a Zn(II)salt and a base are mixed in a solvent in a first reactor forming nano-ZnO particles ii) graphite is exfoliated via impact of ultrasound in a second reactor iii) both suspensions of i) and ii) are mixed together iv) after step iii) the solvent is removed from the suspension. These coated composites may be tempered in a further step and again coated and again tempered.

Solid-state supercapacitors and microsupercapacitors comprising printed graphene electrodes and related methods of preparation.

An energy storage device according to an aspect of the present invention includes: a negative electrode including a negative substrate made of pure aluminum or an aluminum alloy, a conductive layer directly or indirectly layered on the negative substrate and containing a conductive agent, and a negative active material layer containing a negative active material capable of occluding lithium ions at a potential of 0.05 V vs. Li/Li.sup.+ or lower; and a positive electrode opposed to the negative electrode and including a positive substrate and a positive active material layer directly or indirectly layered on the positive substrate, and the negative active material layer is layered on the negative substrate and the conductive layer so as to include a region in contact with the negative substrate and a region in contact with the conductive layer.

An energy storage device according to an aspect of the present invention includes: a negative electrode including a negative substrate made of pure aluminum or an aluminum alloy, a conductive layer directly or indirectly layered on the negative substrate and containing a conductive agent, and a negative active material layer containing a negative active material capable of occluding lithium ions at a potential of 0.05 V vs. Li/Li.sup.+ or lower; and a positive electrode opposed to the negative electrode and including a positive substrate and a positive active material layer directly or indirectly layered on the positive substrate, and the negative active material layer is layered on the negative substrate and the conductive layer so as to include a region in contact with the negative substrate and a region in contact with the conductive layer.

Disclosed is a hybrid electrochemical cell with a first conductor having at least one portion that is both a first capacitor electrode and a first battery electrode. The hybrid electrochemical cell further includes a second conductor having at least one portion that is a second capacitor electrode and at least one other portion that is a second battery electrode. An electrolyte is in contact with both the first conductor and the second conductor. In some embodiments, the hybrid electrochemical cell further includes a separator between the first conductor and the second conductor to prevent physical contact between the first conductor and the second conductor, while facilitating ion transport between the first conductor and the second conductor.

Disclosed is a hybrid electrochemical cell with a first conductor having at least one portion that is both a first capacitor electrode and a first battery electrode. The hybrid electrochemical cell further includes a second conductor having at least one portion that is a second capacitor electrode and at least one other portion that is a second battery electrode. An electrolyte is in contact with both the first conductor and the second conductor. In some embodiments, the hybrid electrochemical cell further includes a separator between the first conductor and the second conductor to prevent physical contact between the first conductor and the second conductor, while facilitating ion transport between the first conductor and the second conductor.

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

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

An ultracapacitor that is capable of exhibiting good properties even after being subjected to high temperatures, such as experienced during solder reflow, is provided. The ultracapacitor contains a housing having sidewalls that extend in a direction generally perpendicular to a base. An interior cavity is defined between an inner surface of the base and the sidewalls within which an electrode assembly can be positioned. To attach the electrode assembly, first and second conductive members are disposed on the inner surface of the base. The electrode assembly likewise contains first and second leads that extend outwardly therefrom and are electrically connected to the first and second conductive members, respectively. The first and second conductive members are, in turn, electrically connected to first and second external terminations, respectively, which are provided on an outer surface of the base.

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.