The present invention relates to an aqueous electrolyte capable of improving low temperature performance. More specifically, the present invention provides an aqueous electrolyte that is an aqueous solution including lithium trifluoromethanesulfonate at a predetermined concentration range without separate additives, and thus can prevent freezing and realize high performance even at a very low temperature of about −30° C. or less, and an energy storage device including the same.

The formation method of graphene includes the steps of forming a layer including graphene oxide over a first conductive layer; and supplying a potential at which the reduction reaction of the graphene oxide occurs to the first conductive layer in an electrolyte where the first conductive layer as a working electrode and a second conductive layer with a as a counter electrode are immersed. A manufacturing method of a power storage device including at least a positive electrode, a negative electrode, an electrolyte, and a separator includes a step of forming graphene for an active material layer of one of or both the positive electrode and the negative electrode by the formation method.

The formation method of graphene includes the steps of forming a layer including graphene oxide over a first conductive layer; and supplying a potential at which the reduction reaction of the graphene oxide occurs to the first conductive layer in an electrolyte where the first conductive layer as a working electrode and a second conductive layer with a as a counter electrode are immersed. A manufacturing method of a power storage device including at least a positive electrode, a negative electrode, an electrolyte, and a separator includes a step of forming graphene for an active material layer of one of or both the positive electrode and the negative electrode by the formation method.

A separator that includes a porous polymer substrate, a first porous coating layer and a second porous coating layer. First inorganic particles contained in the first porous coating layer have a lower hardness as compared to the second inorganic particles contained in the second porous coating layer. Since the separator is provided with at least two porous coating layers including inorganic particles having a different hardnesses, it is possible to increase the dielectric breakdown voltage, and thus to provide a battery with improved safety. It is also possible to reduce deformation of the separator caused by heat or pressure.

A separator that includes a porous polymer substrate, a first porous coating layer and a second porous coating layer. First inorganic particles contained in the first porous coating layer have a lower hardness as compared to the second inorganic particles contained in the second porous coating layer. Since the separator is provided with at least two porous coating layers including inorganic particles having a different hardnesses, it is possible to increase the dielectric breakdown voltage, and thus to provide a battery with improved safety. It is also possible to reduce deformation of the separator caused by heat or pressure.

An electrochemical capacitor includes a plurality of electrode assemblies, each including a positive electrode configured in a rolled sheet form and having both surfaces coated with an active material layer, a negative electrode configured in a rolled sheet form to face the positive electrode and having both surfaces coated with an active material layer, a separator interposed and rolled between the positive electrode and the negative electrode, a positive electrode lead wire electrically connected to the positive electrode of each of the plurality of electrode assemblies, and a negative electrode lead wire electrically connected to the negative electrode of each of the plurality of electrode assemblies.

In one aspect, separator-free energy storage devices are disclosed. Such devices comprise a first electrode and a second electrode. In some embodiments, the first electrode is opposite the second electrode. The first and/or second electrodes are formed from a nanocomposite material. The nanocomposite material includes plurality of carbon nanostructures, each of which is at least partially coated with a layer of material comprising a transition metal oxide. In some embodiments, the coating layer is uniform or substantially uniform in one or more properties.

An electrode includes an insulating surface layer and at least one aligned carbon nanotube fiber embedded in the insulating surface layer. Each of the at least one aligned carbon nanotube fiber has a first end and a second end opposite the first end, and the first end and the second end are separated by a body. Each of the at least one aligned carbon nanotube fiber is composed of a plurality of carbon nanotubes. The first end and the second end are free of the insulating surface layer. The second end is in contact with an electrical conductive material. A method of analyzing an analyte in a sample and a device for energy storage using the electrode are also described.

The present invention relates to novel biocompatible oxygen gas generating devices that can be implanted into a living subject. In certain embodiments, the oxygen gas generating devices can be used to deliver oxygen gas to tissue in a subject, thereby stimulating tissue growth and repair. In other embodiments, the devices operate by electrolytically splitting endogenous water in a subject. In yet other embodiments, the device further comprises an implantable supercapacitor capable of supplying energy to the oxygen gas generating device.

A secondary battery that includes a partial electrode assembly having a planar stacking structure in which a plurality of electrode constituting layers are stacked, the plurality of electrode constituting layers each include a pair of electrodes and a separator therebetween, and at least one of the pair of electrodes includes a double-sided electrode having an electrode material layer on opposed main surfaces of a current collector; and an outermost layer electrode surrounding the partial electrode assembly along at least a portion of a contour of the partial electrode assembly in a cross-sectional view thereof, the outermost layer electrode including a single-sided electrode having an outermost electrode material layer on one main surface of an outermost current collector.