804results about How to "High reversible capacity" patented technology

This invention provides a nanocomposite-based lithium battery electrode comprising: (a) A porous aggregate of electrically conductive nano-filaments that are substantially interconnected, intersected, physically contacted, or chemically bonded to form a three-dimensional network of electron-conducting paths, wherein the nano-filaments have a diameter or thickness less than 1 μm (preferably less than 500 nm); and (b) Sub-micron or nanometer-scale electro-active particles that are bonded to a surface of the nano-filaments with a conductive binder material, wherein the particles comprise an electro-active material capable of absorbing and desorbing lithium ions and wherein the electro-active material content is no less than 25% by weight based on the total weight of the particles, the binder material, and the filaments. Preferably, these electro-active particles are coated with a thin carbon layer. This electrode can be an anode or a cathode. The battery featuring such an anode or cathode exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

The present invention provides an exfoliated graphite-based hybrid material composition for use as an electrode, particularly as an anode of a lithium ion battery. The composition comprises: (a) micron- or nanometer-scaled particles or coating which are capable of absorbing and desorbing alkali or alkaline metal ions (particularly, lithium ions); and (b) exfoliated graphite flakes that are substantially interconnected to form a porous, conductive graphite network comprising pores, wherein at least one of the particles or coating resides in a pore of the network or attached to a flake of the network and the exfoliated graphite amount is in the range of 5% to 90% by weight and the amount of particles or coating is in the range of 95% to 10% by weight. Also provided is a lithium secondary battery comprising such a negative electrode (anode). The battery exhibits an exceptional specific capacity, excellent reversible capacity, and long cycle life.

This invention provides a nano-structured anode composition for a lithium metal cell. The composition comprises: (a) an integrated structure of electrically conductive nanometer-scaled filaments that are interconnected to form a porous network of electron-conducting paths comprising interconnected pores, wherein the nano-filaments have a transverse dimension less than 500 nm; and (b) micron- or nanometer-scaled particles of lithium, a lithium alloy, or a lithium-containing compound wherein at least one of the particles is surface-passivated or stabilized and the weight fraction of these particles is between 1% and 99% based on the total weight of these particles and the integrated structure together. Also provided is a lithium metal cell or battery, or lithium-air cell or battery, comprising such an anode. The battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

This invention provides a hybrid nano-filament composition for use as an electrochemical cell electrode. The composition comprises: (a) an aggregate of nanometer-scaled, electrically conductive filaments that are substantially interconnected, intersected, or percolated to form a porous, electrically conductive filament network comprising substantially interconnected pores, wherein the filaments have an elongate dimension and a first transverse dimension with the first transverse dimension being less than 500 nm (preferably less than 100 nm) and an aspect ratio of the elongate dimension to the first transverse dimension greater than 10; and (b) micron- or nanometer-scaled coating that is deposited on a surface of the filaments, wherein the coating comprises an anode active material capable of absorbing and desorbing lithium ions and the coating has a thickness less than 20 μm (preferably less than 1 μm). Also provided is a lithium ion battery comprising such an electrode as an anode. The battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

This invention provides a process for producing a hybrid nano-filament composition for use in a lithium battery electrode. The process comprises: (a) providing a porous aggregate of electrically conductive nano-wires that are substantially interconnected, intersected, physically contacted, or chemically bonded to form a porous network of electrically conductive filaments, wherein the nano-wires have a diameter or thickness less than 500 nm; and (b) depositing an electro-active coating onto a surface of the nano-wires, wherein the electro-active coating is capable of absorbing and desorbing lithium ions and the coating has a thickness less than 10 μm, preferably less than 1 μm. This process is applicable to the production of both an anode and a cathode. The battery featuring an anode or cathode made with this process exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

This invention provides a hybrid nano-filament composition for use as a cathode active material. The composition comprises (a) an aggregate of nanometer-scaled, electrically conductive filaments that are substantially interconnected, intersected, or percolated to form a porous, electrically conductive filament network, wherein the filaments have a length and a diameter or thickness with the diameter or thickness being less than 500 nm; and (b) micron- or nanometer-scaled coating that is deposited on a surface of the filaments, wherein the coating comprises a cathode active material capable of absorbing and desorbing lithium ions and the coating has a thickness less than 10 μm, preferably less than 1 μm and more preferably less than 500 nm. Also provided is a lithium metal battery or lithium ion battery that comprises such a cathode. Preferably, the battery includes an anode that is manufactured according to a similar hybrid nano filament approach. The battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

Disclosed is a method of producing a hybrid nano-filament composition for use in a lithium battery electrode. The method comprises: (a) providing an aggregate of nanometer-scaled, electrically conductive filaments that are substantially interconnected, intersected, physically contacted, or chemically bonded to form a porous network of electrically conductive filaments, wherein the filaments comprise electro-spun nano-fibers that have a diameter less than 500 nm (preferably less than 100 nm); and (b) depositing micron- or nanometer-scaled coating onto a surface of the electro-spun nano-fibers, wherein the coating comprises an electro-active material capable of absorbing and desorbing lithium ions and the coating has a thickness less than 10 μm (preferably less than 1 μm). The same method can be followed to produce an anode or a cathode. The battery featuring an anode or cathode made with this method exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

Disclosed in the invention are a silicon-carbon composite anode material for lithium ion batteries and a preparation method thereof The material consists of a porous silicon substrate and a carbon coating layer. The preparation method of the material comprises preparing a porous silicon substrate and a carbon coating layer. The silicon-carbon composite anode material for lithium ion batteries has the advantages of high reversible capacity, good cycle performance and good rate performance. The material respectively shows reversible capacities of 1,556 mAh, 1,290 mAh, 877 mAh and 474 mAh/g at 0.2 C, 1 C, 4 C and 15 C rates; the specific capacity remains above 1,500 mAh after 40 cycles at the rate of 0.2 C and the reversible capacity retention rate is up to 90 percent.

The present invention provides a multiple-doped lithium metal oxide and a method of preparing same for use in the positive electrodes of lithium and lithium ion batteries. The intercalation compound of the invention has the formula LiNi.sub.1-x Co.sub.y M.sub.a M'.sub.b O.sub.2, wherein M is selected from the group consisting of Ti, Zr, and combinations thereof, and M' is selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof. The elements in the compounds are present such that x=y+a+b, x is from greater than 0 to about 0.5, y is from greater than 0 to about 0.5, a is from greater than 0 to about 0.15, and b is from greater than 0 to about 0.15.

The invention discloses a preparation method of a silicon and carbon-coated graphene composite cathode material. The technical problem to be solved is to enhance the electronic conductivity of the silicon-based cathode material, buffer the volume effect produced in the process of deintercalation of the lithium in the silicon-based cathode material and enhance the structure stability in the circulation process of the material at the same time. The material is prepared by using a spray drying-thermally decomposing treatment process in the invention. The preparation method comprises the following steps of: evenly dispersing nano silicon and graphite micro powder in a dispersion solution of oxidized graphene, carrying out thermal treatment under an inert protection atmosphere after spray drying, subsequently cooling along a furnace to obtain the silicon and carbon-coated graphene composite cathode material. The extra binder does not need to add in the process of manufacturing balls in the invention and the outer oxidized graphene is thermally reduced in situ to graphene in the thermal treatment process of the composite precursor, so that the process is simple and easy to operate; and the practical degree is high. The prepared composite material has the advantages of great reversible capacity, designable capacity, good cycling performance and high-current discharging performance, high tap density and the like.

The invention has a grain structure with an outer shell and several inner cores. The grain size is from 100 nanometers to 100 microns. The inner cores are compound grain that includes active substance and conducting additive. The outer shell is a carbon layer. The active substance takes 20-95wt% of total cathode active material, and is mixture of one or several transition metallic compound selected from silicon and lithium storage whose thermodynamic equilibrium potential is less than 1.5v. The cathode material can be made by using mechanical process or thermal method, and can be directly used as cathode material or used with other existing cathode material.

The invention discloses a silicon-carbon composite material with nano micropores and a preparation method as well as application thereof. The material comprises nano-silicon (Si) particles and a carbon nanofiber matrix, wherein the nano-silicon particles are dispersed in the carbon nanofiber matrix; and nano pores and micropores communicated with the nano pores are distributed in the carbon nanofiber matrix. The method comprises the steps of dissolving the nano-Si particles and polyacrylonitrile (PAN) in a solvent to prepare a mixed spinning solution, then carrying out electrostatic spinning on the mixed spinning solution, and curing spinning trickles in a coagulating bath to obtain a porous PAN-Si composite nanofiber; and then carrying out oxidation and carbonization treatment in sequence to obtain the silicon-carbon composite material with a nano micropore structure. The silicon-carbon composite material is applied to preparation of lithium ion battery cathode materials. Compared with the prior art, the silicon-carbon composite material ensures the overall electron transport capacity of the material while reserving buffer space for expansion of the nano-Si particles.

The invention discloses a carbon cladded ferriferrous oxide negative electrode material of a lithium ion battery and a preparation method thereof. The negative electrode material is a carbon cladded Fe3O4 composite material and has a particle size in a range of 1 to 100 nm. The preparation method comprises the following steps: with NaCl used as a dispersing agent and a supporter, fully mixing NaCl with a metal oxide source and a solid carbon source; drying an obtained mixed solution under vacuum to obtain a mixture; placing the mixture into a tubular furnace for calcination in an inert atmosphere so as to obtain a calcined product; and rinsing and grinding the calcined product to obtain carbon cladded metal oxide nanometer particles. The method is safe and non-toxic and is simple to operate; during charging and discharging tests of a lithium ion button cell made of the carbon cladded ferriferrous oxide negative electrode material, discharge specific capacity can be maintained at 620 to 900 mAh/g after 30 cycles of charging and discharging at a current of 0.1C (with current density being 92 mA/g), and discharge specific capacity can be maintained at 600 to 760 mAh/g after 50 cycles of charging and discharging at a current of 1C (with current density being 920 mA/g); and the negative electrode material of the lithium ion battery has high reversible capacity and good cycling stability.

The invention discloses a preparation method for a composite cathode material of a lithium ion battery by means of spray drying pyrolysis treatment. The preparation method includes the steps: dissolving a first type of binder organic carbon source into solvent of a proper quantity, adding a silicon source, a second type of binder and a dispersing agent, dispersing uniformly, adding graphite, dispersing for a certain time, subjecting uniformly dispersed suspension to spray drying, and using the first type of binder organic carbon source to bond the silicon source, the graphite and the second type of binder particles into spherical or spherical-like forms to obtain a composite precursor; and transferring the precursor into a shielding atmosphere for sintering, heating the second type of binder to a certain temperature to be melted into a liquid crystal state, bonding the particle silicon source and the graphite into cores, subjecting the organic carbon source to pyrolysis at the high temperature to form a coating, and furnace cooling to obtain the carbon-silicon composite cathode material of the lithium ion battery. The preparation method is simple, easy in implementation and high in practicality. The carbon-silicon composite prepared by the method has the advantages of high reversible capacity, designable capacity, high circulating performance and high-current discharging performance, high tap density and the like.

The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn_2-y-zLi_yM_zO₄ oxide with NH₄HF₂ at low temperatures of between about 300 and 700° C. for 2 to 8 hours and a η of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

The present invention relates to a cathode of a lithium-ion, which comprises a cathode collecting body and a cathode material layer that is coated on the collecting body; the cathode material layer comprises a cathode active substance and an adhesion agent, the cathode active substance comprises a spherical-shaped natural graphite and a squamiform artificial graphite, wherein, the squamiform graphite comprises a large-granularity squamiform artificial graphite and a small-granularity squamiform artificial graphite, the average granularity D50 of the large-granularity squamiform artificial graphite is 20 to 35 micron, the average granularity D50 of the small-granularity squamiform artificial graphite is 1 to 5 micron; adopting the total quantity of the mixing graphite of the spherical-shaped natural graphite, the large-granularity squamiform artificial graphite and the small-granularity squamiform artificial graphite as the standard, the content of the spherical-shaped natural graphiteis 75 percent to 98 percent, the content of the large-granularity squamiform artificial graphite is 1 percent to 20 percent, and the content of the small-granularity squamiform artificial graphite is1 percent to 20 percent. Even the density of the cathode using the cathode active substance reaches 1.8 g/cm<3>, the cathode still has higher capacity and good cycling service life.

Porous silicon and methods for preparation and use of the same are disclosed. The porous silicon materials have utility either alone or in combination with other materials, for example, combined with carbon particles for energy storage applications.

The invention discloses a synthesizing method of anode material of high-pressure solid-phase ferric-lithium phosphate, which comprises the following steps: blending lithium salt, ferric salt and phosphate according to 1:1:1 proportion evenly; grinding the material into ball for 6-24 h to obtain priority; disposing priority for 2-10 h at 200-350 deg.c in the air environment; cooling naturally; grinding to obtain powder material; adding carbon material in the powder material with weight percentage of carbon material at 1-20 percent; grinding again for 6-24 h; disposing for 4-24 h at 450-1000 deg.c in the 1-15 Mpa inert environment; cooling naturally to obtain the product.

The invention discloses a high capacity and stable cyclic performance lithium ion battery electrode and a preparation method thereof. The invention is characterized in that: the electrode comprises the following components in percentage by mass: 75 to 85 percent of graphene nano slice/molybdenum disulfide (MoS2) compound nano material serving as an active substance, and 5 to 10 percent of acetylene black and 5 to 15 percent of polyvinylidene fluoride; and the mass ratio of the graphene nano slice to the MoS2 compound nano material in the compound nano material active substance is (1 to 1)-(4 to 1). The preparation method for the electrode comprises the following steps of: preparing an oxidized graphite nano slice by using graphite as a raw material by a chemical oxidization method; synthesizing by a one-step hydrothermal in-situ reduction method in the presence of the oxidized graphite nano slice to obtain a graphene nano slice/MoS2 compound nano material; and finally, preparing the electrode by using the graphene nano slice/MoS2 compound nano material as the active substance. The electrode has high electrochemical lithium storage reversible capacity and cyclic stabilization performance, and can be widely applied to new generation lithium ion batteries.

A lithium secondary battery according to the present invention includes: a positive electrode having a positive-electrode active material capable of occluding and releasing lithium ions; a negative electrode having a negative-electrode active material capable of occluding and releasing lithium ions; a separator interposed between the positive electrode and the negative electrode; and an electrolyte having lithium-ion conductivity. The positive-electrode active material contains a nickel-type lithium-containing complex oxide. The negative-electrode active material contains a graphite-type material having a reversible capacity of 350 mAh/g or more and an irreversible capacity of 30 mAh/g or less. A ratio Qc/Qa between an irreversible capacity Qc per unit area in a portion of the positive electrode that opposes the negative electrode and an irreversible capacity Qa per unit area in a portion of the negative electrode that opposes the positive electrode is equal to or greater than 0.50 but less than 1.13. As a result, the charge-discharge cycle characteristics can be improved while ensuring a high capacity.

The invention disclosed is a composition of a single-phase solid solution of LiMnO₂ and LiMO₃ having a Li₂MnO₃-type crystallographic structure and the general formula Li_i+y/3Mn_2y/3M_(1−y)O₂, wherein 0<y<1, manganese is in the 4+ oxidation state, M is one or more transition metal or other cations which have an appropriate ionic radii to be inserted into the structure without unduly disrupting it, but not solely Ni or Cr, e.g. one or more the first row transition metals: Ti, V, Cr, Mn, Fe, Co, Ni or Cu, or other specific other cations: Al, Mg, Mo, W, Ta, Si, Sn, Zr, Be, Ca, Ga, and P, and M has an average oxidation state of +3. Also disclosed are compositions and structures of the materials e.g in the form of a positive electrode for a non-aqueous lithium cell or battery.