The present disclosure provides supercapacitors that may avoid the shortcomings of current energy storage technology. Provided herein are electrochemical systems, comprising three dimensional porous reduced graphene oxide film electrodes. Prototype supercapacitors disclosed herein may exhibit improved performance compared to commercial supercapacitors. Additionally, the present disclosure provides a simple, yet versatile technique for the fabrication of supercapacitors through the direct preparation of three dimensional porous reduced graphene oxide films by filtration and freeze casting.

The present disclosure is directed to a phosphorus-modified ionic liquid compound, the synthesis thereof and an electrochemical cell electrolyte containing the phosphorus-modified ionic liquid compound.

The present disclosure is directed to a phosphorus-modified ionic liquid compound, the synthesis thereof and an electrochemical cell electrolyte containing the phosphorus-modified ionic liquid compound.

The present invention is concerned with a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution containing a compound represented by the following general formula (X), in which a polar group (X) is bound to a phosphorus atom (P), and capable of improving electrochemical characteristics in a broad temperature range; an energy storage device using the same; and a novel compound.

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In the formula, R.sup.10 and R.sup.20 are each independently an organic group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms, or a lithium atom; and X is a polar group (i) containing a —C(═O) group, a —P(═O) group, or an —S(═O).sub.2 group, a polar group (ii) containing a —CN group or an alkyl group having 1 to 6 carbon atoms, in which a part of hydrogen atoms is substituted with a fluorine atom, or a 4- to 7-membered ring polar group (iii) containing a —C(═O)—O— group or a —C(═O)—N— group, provided that when X is a 4- to 7-membered ring polar group (iii) containing a —C(═O)—N— group, at least one of R.sup.10 and R.sup.20 is a lithium atom.

The present invention provides a novel electrolyte solution capable of providing electrochemical devices having a high storage capacity retention. The electrolyte solution of the present invention contains a fluorinated phosphoric acid ester containing a non-fluorinated alkylene group having one or more carbon atoms as a linking group.

An apparatus including a first electrode, a second electrode and an electrolyte, the first electrode including graphene oxide and configured to generate protons in the presence of water to produce a potential difference between the first and second electrodes, the electrolyte configured to enable the generated protons to flow from the first electrode to the second electrode when the first and second electrodes are connected by an external circuit, wherein the electrolyte includes a room-temperature ionic fluid configured to absorb water from the surrounding environment and deliver said water to the first electrode to facilitate the generation of protons.

An apparatus including a first electrode, a second electrode and an electrolyte, the first electrode including graphene oxide and configured to generate protons in the presence of water to produce a potential difference between the first and second electrodes, the electrolyte configured to enable the generated protons to flow from the first electrode to the second electrode when the first and second electrodes are connected by an external circuit, wherein the electrolyte includes a room-temperature ionic fluid configured to absorb water from the surrounding environment and deliver said water to the first electrode to facilitate the generation of protons.

An aqueous electrolyte for a capacitor contains at least one transition metal complex. An aqueous electrolyte containing at least one transition metal complex can be used in a supercapacitor, in a pseudocapacitor, or in a hybrid supercapacitor. A hybrid supercapacitor contains an aqueous electrolyte, which contains at least one transition metal complex.

Electrolytes and electrolyte additives for energy storage devices comprising a sulfonate ester compound 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 sulfonate ester compound.

A hybrid supercapacitor has two electrodes, one of which functions as a cathode, and the other as an anode. The hybrid supercapacitor further includes an electrolyte arranged between the cathode and the anode. The electrolyte contains a solvent selected from the group consisting of methanol, 1-propanol, 1-heptanol, ethyl acetoacetate, ethylene glycol, diethylene glycol, glycerol, benzyl alcohol, di-n-butyl phthalate and mixtures thereof.