An energy bank is provided that includes a plurality of integrated energy storage devices comprising a plurality of supercapacitors, a plurality of batteries and a plurality of metal shells. Each of the integrated energy storage devices comprises a supercapacitor, a battery surrounding the supercapacitor and a metal shell surrounding the battery. The battery forms a shell around an exterior surface of the supercapacitor. The battery includes a first anode, a first cathode, and an electrolyte disposed between the first anode and the first cathode. The supercapacitor includes a second anode, a second cathode, and a separator disposed between the second anode and the second cathode.

A composite electrode is provided having a collector, the collector is coated with an electrode composition containing an active electrode material, a binding agent, and a conductivity additive such as conductive carbon black. The electrode composition has a concentration gradient along the direction of the electrode thickness in respect of the active electrode material and the conductivity additive, with the concentration gradient of the active electrode material increasing toward the collector, and the concentration gradient of the conductivity additive and the binder decreasing toward the collector. Two different methods of producing the composite electrode are also provided. A lithium-ion battery is further provided which includes a composite electrode having a collector, the collector is coated with an electrode composition containing an active electrode material, a binding agent, and a conductivity additive.

Provided is a composite electrode material. The composite electrode material is disposed on a surface of an electrode. The composite electrode material includes a plurality of conductive material layers and a plurality of active material layers. The conductive material layers and the active material layers are alternately stacked along a direction non-parallel to the surface of the electrode, and are arranged disorderly along a direction parallel to the surface of the electrode.

Provided is a composite electrode material. The composite electrode material is disposed on a surface of an electrode. The composite electrode material includes a plurality of conductive material layers and a plurality of active material layers. The conductive material layers and the active material layers are alternately stacked along a direction non-parallel to the surface of the electrode, and are arranged disorderly along a direction parallel to the surface of the electrode.

The present invention concerns a method for obtaining polyaniline/reduced graphene oxide composites comprising the steps of dispersing the graphene oxide in an acid aqueous solution containing an emulsifying agent to obtain a graphene oxide dispersion; dissolving one or more aniline oligomers in an organic solvent to obtain an oligomer solution; mixing the oligomer solution with the graphene oxide dispersion, said oligomer being added in a stoichiometric excess compared to the quantity required to complete the graphene oxide reduction; adding to the suspension of the polyaniline/reduced graphene oxide composite an oxidizing agent in a stoichiometric quantity compared to said excess of oligomer so as to oxidize the excess of said oligomer to obtain a suspension of the polyaniline/reduced graphene oxide composite.

The present invention concerns a method for obtaining polyaniline/reduced graphene oxide composites comprising the steps of dispersing the graphene oxide in an acid aqueous solution containing an emulsifying agent to obtain a graphene oxide dispersion; dissolving one or more aniline oligomers in an organic solvent to obtain an oligomer solution; mixing the oligomer solution with the graphene oxide dispersion, said oligomer being added in a stoichiometric excess compared to the quantity required to complete the graphene oxide reduction; adding to the suspension of the polyaniline/reduced graphene oxide composite an oxidizing agent in a stoichiometric quantity compared to said excess of oligomer so as to oxidize the excess of said oligomer to obtain a suspension of the polyaniline/reduced graphene oxide composite.

An electricity storage device includes an electrode assembly and a load applying mechanism. The load applying mechanism applies, to the electrode assembly, a load in a direction in which the positive electrode and the negative electrode are stacked in the electrode assembly. The negative electrode includes a metal foil and an active material layer that covers at least part of the metal foil and contains a carbon-based material as an active material. The density of the carbon-based material in the active material layer is 1.2 g/cm.sup.3 or higher. The degree of orientation that is defined as a ratio (I(100)/I(002)) of an X-ray diffraction intensity I(100) of a (100) plane to a diffraction intensity I(002) of a (002) plane in the active material layer is lower than or equal to 0.3. The load applied by the load applying mechanism is greater than or equal to 0.22 MPa.

A capacitor electrode includes a collector, and an electrode layer disposed in contact with the collector and capable of inserting and releasing cations. The electrode layer includes first carbon material particles capable of inserting and releasing cations and second carbon material particles capable of inserting and releasing cations. The average particle diameter of primary particles of the second carbon material particles is smaller than the average particle diameter of primary particles of the first carbon material particles. In the electrode layer, the content amount of the second carbon material particles is smaller than the content amount of the first carbon material particles.

A capacitor electrode includes a collector, and an electrode layer disposed in contact with the collector and capable of inserting and releasing cations. The electrode layer includes first carbon material particles capable of inserting and releasing cations and second carbon material particles capable of inserting and releasing cations. The average particle diameter of primary particles of the second carbon material particles is smaller than the average particle diameter of primary particles of the first carbon material particles. In the electrode layer, the content amount of the second carbon material particles is smaller than the content amount of the first carbon material particles.

An electric double layer capacitor electrode, including: an activated carbon having: a pore volume utilization efficiency (PVUE) of from about 200 to 290 F/cm.sup.3, wherein PVUE is the ratio of the activated carbon gravimetric capacitance (F/g) to the pore volume (cm.sup.3/g) of the activated carbon; a low non-linearity value of from 0.1 to 5%; and a total pore volume of from 0.32 to 0.56 cm.sup.3/g. Also disclosed is a method of making an electric double layer capacitor electrode, and a method of characterizing the performance of activated carbon, and the electrode, in an electric double layer capacitor (EDLC) device, as defined, herein.