1831results about How to "Improve discharge capacity" patented technology

The present invention relates to a preparation method for a nickel-manganese-cobalt anode material of a lithium ion battery. According to the present invention, in the presence of nitrogen atmosphere, a mixed solution containing nickel iron, manganese iron and cobalt ion reacts with a precipitating agent, then processes of aging, washing, drying and the like are performed to obtain a nickel-manganese-cobalt hydroxide precursor, the synthesized precursor material has spherical morphology, ideal particle size distribution and high tap density; the precursor, a lithium compound and a doped compound are mixed, then the sintering processing is performed for twice to prepare the nickel-manganese-cobalt three-element composite anode material. The method has characteristics of simple synthesis process, easy process controlling, low energy consumption, high efficiency and low cost, and is applicable for the industrial production; the prepared precursor material has characteristics of spherical morphology, uniform particle distribution and high tap density; the discharge capacity of the battery is improved through doping the metals; the cycle performance of the battery is stable.

Disclosed is a negative active material for a rechargeable lithium battery that includes graphite particles, silicon micro-particles attached on the graphite particles and a carbon film partially or totally coated on the graphite particles.

A backup power supply is so constructed that it is provided with multiple DC backup power supplies 111 to 11N, each containing nickel-metal hydride battery, stored upright on the bottom of the disk array unit 100; cooled by cooling air through the vents 1011 for ventilation from the bottom to the top; and connected with the output of the AC/DC converters 121, 122 with the backboard 151. Very compact disk array unit with an uninterruptible power supplying function can be realized.

Graphene is formed with a practically uniform thickness on an uneven object. The object is immersed in a graphene oxide solution, and then taken out of the solution and dried; alternatively, the object and an electrode are immersed therein and voltage is applied between the electrode and the object used as an anode. Graphene oxide is negatively charged, and thus is drawn to and deposited on a surface of the object, with a practically uniform thickness. After that, the object is heated in vacuum or a reducing atmosphere, so that the graphene oxide is reduced to be graphene. In this manner, a graphene layer with a practically uniform thickness can be formed even on a surface of the uneven object.

To provide graphene through which ions can transfer in the direction perpendicular to a plane of the graphene. Multilayer graphene includes a plurality of graphenes stacked in a layered manner. The plurality of graphenes contain a six-membered ring composed of carbon atoms, a poly-membered ring which is a seven or more-membered ring composed of carbon atoms or carbon atoms and one or more oxygen atoms, and an oxygen atom bonded to one of the carbon atoms in the six-membered ring and the poly-membered ring, which is a seven or more-membered ring. The interlayer distance between adjacent graphenes of the plurality of graphenes is greater than 0.34 nm and less than or equal to 0.5 nm, preferably greater than or equal to 0.38 nm and less than or equal to 0.42 nm.

The invention relates to a power type lithium battery full-automatic production line and a production technology thereof. The power type lithium battery full-automatic production line mainly consists of a pole piece manufacturing unit, a battery assembling unit, a battery liquid injecting unit and a factory processing unit; each unit key equipment electrical control system is composed of a PLC, an industrial personal computer, a hydraulic and pneumatic component; the PLC controls each mechanism of the equipment to act in a coordinated manner; and the industrial personal computer collects data to realize the function that the data of the whole line can be stored, read and the like. The main effects lie in that mutual matching of production efficiency of each unit is realized through key debugging for production parameters, a conveyor is adopted in an intermediate link, and full automation of production process is finally realized; the production line is compatible with multi-standard battery production requirements, the production when the product is remodeled can be realized just by adjusting the equipment parameters and replacing partial work fixtures, and order form-based production requirement of the product is met; key equipment and technology on the line are independently researched and developed, the operation is reliable and stable, and the production line has higher cost performance.

A method of preparing LiFePO₄/Li₃V₂(PO₄)₃ composite cathode materials and their applications as cathode materials for lithium ion batteries are disclosed. The preparation method includes the following steps: (A) providing a mixture of iron powder, lithium salt, vanadium salt, and a phosphate salt whereafter these compounds are dissolved into a mixed acid solution; (B) drying the solution in order to obtain precursor powders; and (C) heating the precursor powders at a temperature ranging between 400 and 1000° C. to form LiFe_1-y′V_y′PO₄/Li₃V_2-y″Fe_y″(PO₄)₃ composite powders. Alternatively, prepare the composite cathode by preparing olivine LiFe_1-y′V_y′PO₄ and monoclinic Li₃V_2-y′Fe_y″(PO₄)₃ powders as in previous procedures followed by mixing adequately. The low cost of iron powder thus facilitates to prepared composite cathode materials exhibiting higher electrical conductivity and superior cycling performance at high C rates than those of olivine LiFe_1-y′V_y′PO₄ and monoclinic Li₃V_2-y″Fe_y″(PO₄)₃. The invention will help the development of the lithium ion batteries and related industries.

The invention discloses a cathode material of a lithium ion battery, a preparation method of the cathode, and the lithium ion battery using the cathode material, belonging to the technical field of energy material. According to the invention, a chemical dispersant is added into the cathode of an aqueous lithium-ion battery, thereby solving problems of uniform dispersion for active materials of positive electrode and a nano-carbon mixed conductive agent; and a mechanical dispersion method is combined, preferably with a revolution speed of the mechanical dispersion being 15-35 HZ and a rotation speed being 10-30 HZ, thereby realizing uniform dispersion of the nano-active substances in a relatively short time. The cathode material of a lithium ion battery and the preparation method provide technical approach for solving uniform dispersion of the aqueous nano-active substances, and are high in production efficiency and low in cost; the prepared battery is high in discharge capacity, and is significantly improved in low temperature, multiplying power and cycling performances; and a new approach is provided for a large scale application of the nanometer lithium batteries which are limited to a high cost and a high-polluting oil system in the field.

To provide a lithium-ion secondary battery having higher discharge capacity and higher energy density and a manufacturing method thereof. The lithium-ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte provided between the positive electrode and the negative electrode. The positive electrode includes a positive electrode current collector and a positive electrode active material layer provided over the positive electrode current collector. In the positive electrode active material layer, graphenes and lithium-containing composite oxides are alternately provided. The lithium-containing composite oxide is a flat single crystal particle in which the length in the b-axis direction is shorter than each of the lengths in the a-axis direction and the c-axis direction. Further, the lithium-containing composite oxide is provided over the positive electrode current collector so that the b-axis of the single crystal particle intersects with a surface of the positive electrode current collector.

The invention relates to a method for synthesizing LiFePO4/C material by chemical vapor deposition supporting the solid phase reaction method, namely, the method for preparing carbon coating lithium iron battery anode material, belonging to the Li-ion battery material preparation art technical field. The characteristics of the method for synthesizing LiFePO4/C materials by solid phase and auxiliary chemical vapor deposition are that auxiliary chemical vapor deposition supporting the solid phase reaction method is adopted to synthesize the carbon coating phosphate lithium iron, namely, the LiFePO4/C material. In the method for synthesizing LiFePO4/C material by chemical vapor deposition supporting the solid phase reaction method, a precursor comprising raw materials of lithium, iron and phosphor is adopted to prepare the carbon coating phosphate lithium iron after being blended, grinded by a globe mill, treated by preheating and calcined as well as vapor deposition. The method for synthesizing LiFePO4/C material by chemical vapor deposition supporting the solid phase reaction method has the advantages that the chemical composition, carbon contents and grain size of LiFePO4 can be controlled effectively; the Li-ion battery anode material prepared has sound conductive performance and can improve the charge-discharge rate and cycling performance of the material.

The invention relates to a high-capacity graphite material and a preparation method as well as application thereof. The high-capacity graphite material comprises artificial graphite and natural graphite, wherein the mass ratio of artificial graphite to natural graphite is 20:1 to 1:1. According to the preparation method, the artificial graphite and the natural graphite are uniformly mixed according to a certain mass ratio, and then surface modification is carried out on the mixture. The prepared graphite material has the advantages of high discharge capacity, high first efficiency, long cycle life, low cost and the like; the discharge capacity of the high-capacity graphite material can reach up to more than 350mAh/g (even reach up to more than 368mAh/g); a half-cell of the high-capacity graphite material charges and discharges at the 1C multiple power; after the high-capacity graphite material cycles for 100 times, the capacity retention ratio of the high-capacity graphite material is still more than 90% (even reaches up to more than 96.3%); the first efficiency reaches up to more than 95.5%; and the manufacturing cost is reduced by about 1-10%. The high-capacity graphite material provided by the invention not only can meet the requirement of a lithium ion power battery for the high multiplying power charge-discharge of the material, but also reduces the manufacturing cost of the cathode material of the lithium ion battery.

The invention discloses a method for preparing polyaniline coating Li-ion battery anode material LiFePO4. The method is coating polyaniline on the in-situ surface of the powder of Li-ion battery anode material LiFePO4. The method has the following favorable effects: the discharging voltage platform of the polyaniline coating anode material LiFePO4obtained is stable, the battery has higher specific capacity up to one hundred and forty point three mAh/g, the granularity is distributed evenly, the grains are in good appearance and high in discharging capacity and long in cycling life, etc.

An electrode for a battery in which a collector and an electrode tab are connected with a novel connection structure without impairing electrical connection, and a method of manufacturing the electrode quite simply are provided. Further, a battery having this electrode for the battery is provided. A collector (2) and a tab (3) are connected via a graphite layer (4). The graphite layer is formed on the surface of the collector to be connected with the tab and/or the surface of the tab to be connected with the collector, the portions to be connected of the collector and the tab are overlapped on each other with the graphite layer interposed between the collector and the tab, and a pressure is applied to the overlapped portions to connect the collector (2) with the tab (3). It is preferable that the collector (2) is made of a conductive thin film formed on a resin film (5).

Methods of fabricating porous silicon by electrochemical etching and subsequent coating with a passivating agent process are provided. The coated porous silicon can be used to make anodes and batteries. It is capable of alloying with large amounts of lithium ions, has a capacity of at least 1000 mAh/g and retains this ability through at least 60 charge/discharge cycles. A particular pSi formulation provides very high capacity (3000 mAh/g) for at least 60 cycles, which is 80% of theoretical value of silicon. The Coulombic efficiency after the third cycle is between 95-99%. The very best capacity exceeds 3400 mAh/g and the very best cycle life exceeds 240 cycles, and the capacity and cycle life can be varied as needed for the application.

Disclosed is a phosphorus-doped lithium iron phosphate positive electrode material and a preparation method of the same, which relates to a positive electrode materials of lithium ion batteries. The present invention provides a phosphorus-doped lithium iron phosphate positive electrode material of lithium ion batteries with higher charge-discharge capacity, excellent multiplying power performance and cycle performance, and a preparation method of the same. The positive electrode material has a formula of LiyFe(P1-xMx)O4, wherein M is doping element of Ge, Sn, Se, Te or Bi. The preparation method comprises the steps of mixing the ferrite and phosphate with dopant; adding at least one of the water, alcohol, acetone serving as ball mill solvent; scrubbing and filtrating after ball milling; vacuum drying the filtration product to obtain the intermediate product which is mixed with lithium salt; adding ball mill solvent to ball mill again; drying the product and then heating calcining in the presence of inert gas or reducing atmosphere to obtain doping type lithium iron phosphate LiyFe(P1-xMx)O4 powder.

[Object]

There is provided an active material for a lithium secondary battery, which has a high initial efficiency and a high discharge capacity, and particularly has a high discharge capacity at a low temperature (excellent low-temperature characteristic), and a lithium secondary battery using the active material.

[Solution]

An active material for a lithium secondary battery, which contains a solid solution of a lithium transition metal composite oxide having an α-NaFeO₂ crystal structure, wherein the composition ratio of metal elements contained in the solid solution satisfies, Li_1+x−yNa_yCo_aNi_bMn_cO_2+d (0<y≦0.1, 0.4≦c≦0.7, x+a+b+c=1, 0.1≦x≦0.25, −0.2≦d≦0.2), the active material has an X-ray diffraction pattern attributable to a space group R3-m (P3₁12), and in the Miller index hkl, the half width of the diffraction peak of the (003) is 0.30° or less and the half width of the diffraction peak of the (114) plane is 0.50° or less. Further, the average of three oxygen position parameters determined from crystal structure analysis by the Rietveld method on the basis of the X-ray diffraction pattern is preferably 0.264 or less.

In a hand warmer, a heat dissipating plate is thermally coupled to a heater that is supplied with current by a battery that is accommodated in a case. The battery is a box-shaped rechargeable battery of a box-shaped rechargeable lithium-ion battery or lithium-polymer battery that has flat surfaces opposed to each other. The heater is a heating element that is opposed to the flat surface of the battery. A shielding plate is arranged between the heating element and the flat surface of the battery. The heat dissipating plate that is thermally coupled to the heating element is secured to the case on the surface side of the case. In the hand warmer, the flat surface of the box-shaped rechargeable battery, the shielding plate and the heat dissipating plate are arranged in a stack structure. The heat dissipating plate is heated by the heating element.

The invention relates to a carbon-sulphur composite used for a cathode material of a lithium sulphur battery as well as a preparation method and application thereof. The carbon-sulphur composite comprises a carbon material and elemental sulphur, wherein the carbon material is formed by doping mesoporous carbon with the aperture of 2-5nm and electroconductive carbon with the aperture of 30-70nm, and the electroconductive carbon with the aperture of 30-70nm contains micropores with the aperture of 0.5-1.7nm; and the elemental sulphur accounts for 10-90wt% of the total quantity of the composite. Abundant micropores guarantee that the carbon material has larger specific surface, adsorption capacity to polysulphide is stronger, and dissolution of the polysulphide can be effectively limited, so that stability of a sulphur electrode is improved. Meso pores in porous distribution can load more sulphur active substances, electrochemical capacity of a composite material is improved, and diffusion and transmission of lithium ions and electrolyte solution can be facilitated, so that reduction polarization of the elemental sulphur is reduced and discharge plateau of the elemental sulphur is improved.

The present invention includes compositions, surface and bulk modifications, and methods of making of (1−x)Li[Li_1/3Mn_2/3]O₂.xLi[Mn_0.5-yNi_0.5-yCo_2y]O₂ cathode materials having an O3 crystal structure with a x value between 0 and 1 and y value between 0 and 0.5, reducing the irreversible capacity loss in the first cycle by surface modification with oxides and bulk modification with cationic and anionic substitutions, and increasing the reversible capacity to close to the theoretical value of insertion/extraction of one lithium per transition metal ion (250-300 mAh/g).