The invention discloses a light-emitting diode, comprising a semiconductor substrate with a first conduction type, an active layer on the surface of the semiconductor substrate and a semiconductor covering layer provided with the active layer surface and a second conduction layer, wherein an electrode is arranged on one surface, opposite to the active layer, of the semiconductor covering layer and comprises a graphene layer and a metal layer, and the graphene layer is arranged between the metal layer and the semiconductor covering layer to improve ohmic contact between the metal layer and semiconductor materials. The light-emitting diode has the advantage that through inserting the graphene layer, the surface electronic state of the semiconductor materials can be changed greatly without a process of annealing or etching and the like, thereby reducing contact barrier between any metal or alloy and a semiconductor.

Light-emitting diode

A positive-electrode active material with improved electrical conductivity, and a power storage device using the material are provided. A positive-electrode active material with large capacity, and a power storage device using the material are provided. A core including lithium metal oxide is used as a core of a main material of the positive-electrode active material, and one to ten pieces of graphene is used as a covering layer for the core. A hole is provided for graphene, whereby transmission of a lithium ion is facilitated, resulting in improvement of use efficiency of current.

Positive-electrode active material and power storage device

An energy storage device having high capacity per weight or volume and a positive electrode active material for the energy storage device are manufactured. A surface of a main material included in the positive electrode active material for the energy storage device is coated with two-dimensional carbon. The main material included in the positive electrode active material is coated with a highly conductive material which has a structure expanding two-dimensionally and whose thickness is ignorable, whereby the amount of carbon coating can be reduced and an energy storage device having capacity close to theoretical capacity can be obtained even when a conduction auxiliary agent is not used or the amount of the conduction auxiliary agent is extremely small. Accordingly, the amount of carbon coating in a positive electrode and the volume of the conduction auxiliary agent can be reduced; consequently, the volume of the positive electrode can be reduced.

Method for manufacturing positive electrode active material for energy storage device and energy storage device

The invention discloses a method for compounding graphene and a metallic oxide/metallic compound. The method comprises the following steps: a, dissolving graphene oxide in a dispersing agent, regulating the PH value of the solution to be 5-9, and preparing a graphene oxide solution; and b, adding the oxide/metallic compound into the graphene oxide solution, ultrasonically mixing, reacting at the temperature of 70-120 DEG C for 32-40 hours. According to the method for compounding graphene and the metallic oxide/metallic compound, a reducing agent is not used, the composite material is reduced by utilizing the reducing property of graphene oxide in a hydrothermal environment, and the final product forms the uniformly dispersed graphene and oxide/metallic compound composite material by utilizing the high water solubility of the graphene oxide; and moreover, according to the material, the cycle performance, rate capability and gram volume of the oxide which serves as an electrode of a lithium ion battery can be effectively improved, and the impendence is reduced.

Method for compounding graphene and metallic oxide/metallic compound and composite material thereof

The invention discloses a preparation method of graphene. Specifically, graphite oxide prepared by existing technology is dispersed in a green reducing agent, and oxygen on the graphite oxide is removed through an unbalance reaction in hot water, so that the graphite oxide is reduced into graphene. The graphene prepared by the method provided by the invention has low oxygen content and high conductivity; the method has advantages of simple operation, low cost and high efficiency, and really realizes graphene preparation in kilogram level; no reducing agent severely harmful to the environment or strongly toxic is used; therefore, the method causes no environmental pollution, greatly simplifies the growth process, suits industrial production, and has potential application value in the fields based on graphene.

Preparation method of graphene

Transparent conducting electrode based on graphene and manufacture method and applications thereof

The invention discloses a method for preparing a graphene-doped anode material for lithium-ion batteries. The main component of the anode material is lithium iron phosphate nanoparticles. The method comprises the following steps of: firstly preparing the graphene, graphene oxide, and intercalation graphene respectively; secondly, doping the mixture of the graphene, the graphene oxide and the intercalation graphene in the synthetic material of the lithium iron phosphate nanoparticles or directly mixing the lithium iron phosphate nanoparticles and the intercalation graphene, the graphene oxide,or chemically reduced graphene after the preparation of lithium iron phosphate nanoparticles; and finally, synthesizing the graphene or graphene oxide bridged or lithium iron phosphate nanoparticle-clad material after the treatment of drying, filtering, eluting, re-drying, and annealing. The lithium iron phosphate nanoparticles prepared by the method of the invention are characterized by the capability of greatly improving electron conductivity and providing the lithium-ion batteries anode material having the advantages of simple processing technique, low cost, high capacity and safety for lithium-ion batteries.

Method for preparing graphene-doped anode material for lithium-ion batteries

The invention discloses a graphene and semiconductor nano particle compound system and a synthesizing method thereof in the field of nano materials. The compound system comprises a single or multiple graphite sheet layers and semiconductor nano particles, wherein the graphite sheet layers and the semiconductor nano particles are carried out noncovalent compounding with graphene in solution by pyridine, pyrene or a derivative containing a pi bond or hydroxyl or carboxyl is modified on the graphite sheet layers by a chemical oxidation reduction method, and the amino modification is carried out on the surface of the semiconductor nano particles; and the graphene and semiconductor nano particle compound system is formed by the covalent combination of the hydroxyl or carboxyl and amino. The invention can really improve the interface geometrical contact and energy matching of the graphene and the semiconductor nano particles and creates beneficial condition for the industrial application of a photoelectric device based on the compound system.

Graphene and semiconductor nano particle compound system and synthesizing method thereof

The invention discloses a method for electrochemically preparing graphene, which preferably comprises the steps of pressing a high-purity graphite raw material to form a graphite electrode, carrying out anodization through the graphite electrode by using sulfuric acid aqueous solution or acetic acid and the like mixed acid solution as an electrolyte to prepare a graphite intercalation product, and obtaining expanded graphite by high temperature or microwave and other methods; and then pressing the expanded graphite to prepare a reaction electrode, and carrying out secondary electrochemical intercalation and expansion to finally obtain laminar graphene. According to the invention, in the preparing process, potassium permanganate and other strong oxidizers are not used, and the damage of the strong oxidizers to the structure and performance of graphene are avoided; alkali metal, fuming sulfuric acid oxydol and other inflammable and explosive dangerous substances are not used, and toxic or harmful substances are not introduced, so that the production is safe and environment friendly; and at the same time, the method is simple in process flow, easy to operate, low in cost, high in yield, mild in reaction conditions and low in energy consumption, and is suitable for industrialized large-scale production.

Method for electrochemically preparing graphene

The invention discloses a method for preparing an alternating current electrophoresis directionally assembled carbon nanotube array sensing device, which is characterized by comprising the following steps: making a diagram of an alternating-current electrophoresis metal electrode by using a photoetching method or a metal deposition method; growing a graphene film on the alternating-current electrophoresis metal electrode; applying alternating-current electrophoresis to ultrasonically dispersed carbon nanotubes by using the graphene-covered metal electrodes to perform directional assembly to form a carbon nanotube array; removing or oxidating metal tubes in the carbon nanotube array by using an overload current burning method or an ultraviolet lighting method, or simultaneously removing the metal tubes in the carbon nanotube array by combining the two methods; and modifying the directional carbon nanotube array with metal nanometer particles or polymers. The method uses the graphene-covered metal electrode as the alternating-current electrophoresis electrode to prepare a high-performance directional high-intensity carbon nanotube array field effect device, improves the sensitivity and the detection selectivity of the device, and can realize the high-sensitivity portable detection of gas which pollutes the environment.

Method for manufacturing alternating current electrophoresis directionally assembled carbon nanotube array sensing device

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