A dual-function supercapacitor carbon fiber composite stores electrical energy and functions, for example, as the body shell of electric vehicles (EVs). This is achieved with a vertically aligned graphene on carbon fiber electrode, upon which metal oxides were deposited to obtain ultra-high energy density anode and cathode. A high-strength multilayer carbon composite assembly is fabricated using an alternate layer patterning configuration of epoxy and polyacrylamide gel electrolyte. The energized composite delivers a high areal energy density of 0.31 mWh cm.sup.−2 at 0.3 mm thickness and showed a high tensile strength of 518 MPa, bending strength of 477 MPa, and impact strength 2666 J/m. To show application in EVs, a toy car body fabricated with energized composite operates using the energy stored inside the frame. Moreover, when integrated with a solar cell, this composite powered an IoT (interne of things) device, showing feasibility in communication satellites.

One aspect of the present invention is a positive electrode for an energy storage device including a positive active material layer, in which the positive active material layer includes a positive active material particle having a ratio of a secondary particle size to a primary particle size of 3 or less, and a fibrous conductive agent.

Graphene electrodes-based supercapacitors are in demand due to superior electrochemical characteristics. However, commercial applications have been limited by inferior electrode cycle life. A method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically-stacked and electrically connected to the carbon fibers which results in vertically-aligned graphene-carbon fiber nanostructure is disclosed. The vertically-aligned graphene-carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous three-dimensional architecture which enabled faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F g.sup.−1. The electrodes have electrochemical cycling stability of more than 100,000 cycles with 100% capacitance retention. Apart from the electrochemical double layer charge storage, the oxygen-containing surface moieties and α-Ni(OH).sub.2 present on the graphene sheets enhance the charge storage by faradaic reactions. This enables the assembled device to provide a gravimetric energy density of 76 W h kg.sup.−1 with a 100% capacitance retention even after 1,000 bending cycles.

Graphene electrodes-based supercapacitors are in demand due to superior electrochemical characteristics. However, commercial applications have been limited by inferior electrode cycle life. A method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically-stacked and electrically connected to the carbon fibers which results in vertically-aligned graphene-carbon fiber nanostructure is disclosed. The vertically-aligned graphene-carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous three-dimensional architecture which enabled faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F g.sup.−1. The electrodes have electrochemical cycling stability of more than 100,000 cycles with 100% capacitance retention. Apart from the electrochemical double layer charge storage, the oxygen-containing surface moieties and α-Ni(OH).sub.2 present on the graphene sheets enhance the charge storage by faradaic reactions. This enables the assembled device to provide a gravimetric energy density of 76 W h kg.sup.−1 with a 100% capacitance retention even after 1,000 bending cycles.

Electrochemical devices, such as batteries, supercapacitors, etc., which may be prepared from nanoscopic electrically conductive carbon materials, and optionally electrochemically active materials. Also, methods for preparing such electrochemical devices, including components, elements, etc., of such devices by using three-dimensional (3D) printing, fused deposition modeling (FDM), selective laser sintering (SLS), etc., techniques.

Electrochemical devices, such as batteries, supercapacitors, etc., which may be prepared from nanoscopic electrically conductive carbon materials, and optionally electrochemically active materials. Also, methods for preparing such electrochemical devices, including components, elements, etc., of such devices by using three-dimensional (3D) printing, fused deposition modeling (FDM), selective laser sintering (SLS), etc., techniques.

According to the invention there is provided a component including a supercapacitor and a method of producing same. The component comprises a first (12) and second (14) electrode and a separator structure (16) which separates the two electrodes and contains a liquid or gel electrolyte. The first and second electrode structures are each formed from a composite material (10) which includes electrically conductive fibers and electrochemically active material in a binder matrix and the supercapacitor is formed to be structurally inseparable from the rest of the component. Further, the component forms a structural capacitor. The obtained structural capacitor could be used in aircraft structure to save weight.

According to the invention there is provided a component including a supercapacitor and a method of producing same. The component comprises a first (12) and second (14) electrode and a separator structure (16) which separates the two electrodes and contains a liquid or gel electrolyte. The first and second electrode structures are each formed from a composite material (10) which includes electrically conductive fibers and electrochemically active material in a binder matrix and the supercapacitor is formed to be structurally inseparable from the rest of the component. Further, the component forms a structural capacitor. The obtained structural capacitor could be used in aircraft structure to save weight.

The present invention relates to an elastic fiber electrode including a hybrid fiber prepared by coating a carbon nanotube sheet on a polymer fiber, in which the hybrid fiber is in a yarn form having a coiled structure, and the carbon nanotube sheet makes a wrinkled surface, and a coil- or spring-type elastic fiber electrode manufactured by coiling a hybrid nanofiber prepared by coating a carbon nanotube sheet on a polymer fiber has excellent mechanical and electrical properties. In particular, the elastic fiber electrode has increased porosity by depositing manganese dioxide on a surface thereof, thereby enhancing electrochemical performance. Thus, a micro-supercapacitor using the elastic fiber electrode has high current density and excellent capacitance retention, may maintain the electrochemical characteristics even after being subjected to various deformations, such as bending, coiling, or weaving, and has high elasticity and reversible behaviors, thus providing stable capacitance.

An electrode having a planar electrode body with a plurality of hexagonally shaped through-holes formed therein. The planar electrode body is configured for use in a polar, protic, or aprotic solvent of a Hydro-Pyroelectrodynamic (“H-PED”) energy storage device. The electrode may be constructed using a method that includes applying a layer of graphene to an outer surface of the planar electrode body, and annealing the outer surface of the planar electrode body after the layer of graphene has been applied thereto.