9655 results about "Cyclic stability" patented technology

The invention belongs to the fields of material synthesis and energy technology, and especially relates to a graphene/metal oxide composite cathode material for lithium ion batteries and a preparation method thereof. Grapheme is dispersed into various metal oxide precursor salt solutions; a graphene/metal oxide compound is obtained directly by a hydrothermal method, or an graphene/metal oxide compound is obtained by a liquid in-situ polymerization method or a coprecipitation process; and the graphene/metal oxide compound is obtained by heat treatment or hydrothermal treatment. In the invention, the novel three-dimensional composite cathode material of graphene-coated metal oxide or graphene-anchored metal oxide is prepared by carrying metal oxide particles with graphene as a carrier. The obtained composite material can be used as a lithium ion battery cathode, which has a high specific capacity, excellent cycle stability and rate capability, and is expected to be used as a lithium ion battery cathode material with a high energy density and a high power density.

The invention discloses an electrode material of composite lithium titanate and its preparation method, which is secondary particles with spherical or similar spherical shape and porous nanometer channels, which is made from lithium titanate particles, nano-carbon coated materials and doped modifier. The preparation method includes: milling the inorganic lithium salt, titanium dioxide, nano-carbon coated material or doped modifier, scattering them into the organic solvent for further drying, processing heat treatment, and cooling. Comparing with the existing technologies, this electrode material has the high-rate performance, highly reversible electrochemical capacity, and smaller surface area to enhance its first Coulomb efficiency and cycle stability, applying to rechargeable and once-use lithium-ion battery.

The invention provides a multi-element composite nano-material for a super capacitor, and a preparation method of the nano-material. The nano-material comprises a carbon material, metal oxide and conducting polymer, and components of the nano-material can be two or more than two materials. By the aid of the characteristics such as fine electrical conductivity, long cycle life and high specific surface area of the carbon material, high pseudo-capacitance of the metal oxide and low internal resistance, low cost and high operating voltage of the conducting polymer, different types of electrode materials generate synergistic effects, advantages are mutually combined, shortcomings are mutually weakened, the energy storage characteristics of an electric double-layer capacitor and a pseudo-capacitor are simultaneously made full use of, a composite electrode material with high power density, fine circulating stability and higher energy density is prepared, and the multi-element composite nano-material is excellent in comprehensive performance when used for an electrode of the super capacitor, has the advantages of simple preparation process, short cycle, low cost and the like, and is suitable for large-scale industrial production.

The subject of the invention is an anode material of the silicon-carbon composite type, for a lithium cell, having a high mass capacity and good cycling stability. This material is obtained by a preparation method comprising the steps consisting of:

• • a) providing a silicon powder obtained by the plasma-enhanced chemical vapour deposition (PECVD) technique or by CO₂ laser, the size of the silicon particles being less than 100 nm; b) mixing the silicon powder with a carbon-containing polymer, and c) carrying out the pyrolysis of the mixture. The invention also proposes a lithium cell containing at least one anode the material of which contains the nanocomposite material produced by this method.

The invention discloses a grapheme/silicon composite material for a lithium ion battery cathode material and a preparation method thereof, belonging to the fields of electrochemistry and new energy materials. The method comprises the following steps of: using graphite as a raw material; oxidizing the graphite into oxidized graphite by adopting oxidants of concentrated sulfuric acid and potassium permanganate; then, ultrasonically stripping the oxidized graphite to prepare oxidized graphene; mixing oxidized graphene in different proportions with nano silicon powder; ultrasonically dispersing, filtering or directly drying into a cake/film; and roasting under a reduction atmosphere to prepare self-support graphene/silicon composite film materials in different proportions. Proved by electrochemistry tests, the graphene/silicon composite film material prepared by the method has higher specific capacity and cycle stability, simple preparation method and easy mass production and consequently is an ideal high-energy lithium ion battery cathode material.

The invention discloses a method for preparing graphene aerogel and graphene/ metallic oxide aerogel. The method is characterized in that graphite oxide aqueous solution serves as a raw material, alcohol serves as a cross-linking agent, a precursor solution is obtained through the simple mixing and dispersing processes, the hydrothermal method is adopted, the freeze drying method or a supercritical drying method is adopted, and then the graphene aerogel is obtained . The graphene/ metallic oxide aerogel can be prepared by adding metallic oxide into the polymeric precursor solution. On one hand, the graphene vinyl aerogel material has the characteristic of the graphene aerogel, and on the other hand, the graphene vinyl aerogel material can have the physicochemical characteristic of the metallic oxide. In addition, the aerogel material has a large specific surface and good electrical conductivity, can directly serve as a supercapacitor electrode, and has large specific capacity, good rate capability and cycling stability. The materials used in the method are low in cost, the industrial process is simple, and the method is friendly to the environment.

A preparation method of a high power capacity lithium ion battery cathode material uses natural spherical graphite to serve as raw materials, uses concentrated sulfuric acid to serve as an inserting layer agent, uses potassium permanganate to serve as an oxidizing agent, conducts expansion treatment at high temperature to obtain micro-expanded graphite, then enables the micro-expanded graphite in different proportions to be mixed with nanometer ganister sand, conducts ultrasonic dispersion, suction filtration and dying to obtain the micro-expanded graphite with the nanometer ganister sand inserted in layers, enables the micro-expanded graphite to be mixed and coated with carbon source carbon source according to certain proportion, and finally conducts carburizing sintering under inert gas shielding to prepare completely coated silicon carbon composite cathode material with sufficient obligated obligate inside. Electrochemistry shows that the silicon carbon composite material prepared by the preparation method has high specific capacity and cycling stability and is the ideal high power capacity lithium ion battery cathode material.

The invention relates to a lithium battery with a polymer-coated sulfur/carbon composite material as an anode. According to the invention, sublimed sulfur or sulfur powder and a conductive carbon material are mixed according to a mass ratio of 3:7-8:2; the mixture is subject to ball milling, such that a sulfur/carbon composite material is obtained; the composite material is dispersed in a solution, and a polymer monomer is added to the solution; under a low temperature and the protection of inert gas, an oxidizing agent is added for initiating polymerization; the material is centrifuged, washed, and dried; the obtained polymer-coated elemental sulfur/carbon composite material, acetylene black and PTFE are mixed; a dispersant is added to the mixture, and the mixture is sufficiently mixed by stirring; the mixture is rolled into a sheet, and is vacuum-dried under a temperature of 55 DEG C, such that an electrode sheet is obtained. The prepared electrode sheet is adopted as an anode, metal lithium is adopted as a cathode, and a solvent type organic solution system containing 0.2mol/L of a waterless lithium nitrate additive is adopted as electrolyte, and a battery is assembled. With the electrode material, the assembled lithium battery is advantaged in high specific capacity, good circulation stability, and excellent heavy-current charge/discharge performances. The preparation method is advantaged in simple process, low cost, and good repeatability.

The invention relates to the technical field of energy storage material, in particular to inorganic phase change energy storage material. The material comprises the following components by mass: 70 to 99.5 % of energy storage material, 0.25-20 % of nucleating agent, 0.1-15 % of modifying agent and 0.1-15 % of water. The bases hydrate or crystalline hydrous salt, especially the bases hydrate is adopted as energy storage material; the nucleating agent adopts carbonate; and the modifying agent is dispersant. According to the inorganic phase change energy storage material, by selecting proper nucleating agent and the ration of the nucleating agent, material phase separation can be effectively solved, especially the phase change energy storage material prepared by adding the dispersant into a system has good cycling stability, and simultaneously the potential heat value does not change after circulation for thousands of times.

There are provided an anode for a lithium metal polymer secondary battery comprising an anodic current collector having a surface on which a plurality of recesses having a predetermined shape are formed and a method of preparing the same. The plurality of recesses are formed on a surface of the anodic current collector using a physical method or a chemical method. In a lithium metal polymer secondary battery employing the anode, oxidation/reduction of lithium and the formation of dendrite occur only in the recesses formed by surface patterning of the anodic current collector. Thus, expanding and shrinking of a battery due to a change in the thickness of the lithium anode can be prevented and cycling stability and the lifespan of a battery can be improved.

The invention discloses a preparation method of a spherical doped Al-Ni lithium cobalt oxide for lithium-ion battery. The preparation steps are that: first, sulfate, nitrate or chlorate of Al-Ni-Co react with strong alkali that is added with complex agent in liquid phase; the pH value, the temperature and the feeding speed of the reaction solution are controlled so as to produce a spherical precursor of Al-Ni-Co hydroxide; then the spherical precursor of Al-Ni-Co hydroxide is dried and evenly mixed with lithium hydroxide, lithium nitrate or lithium carbonate and dried; the obtained mixture is roasted into a spherical doped Al-Ni lithium cobalt oxide. The spherical doped Al-Ni lithium cobalt oxide has comparatively high tap density and remarkable cycle stability in the process of high-rate charge/discharge cycle, which improves over charge performance of Ni-Co substance and first obviously enhances charge/discharge efficiency; in addition, the preparation method of the spherical doped Al-Ni lithium cobalt oxide has the advantages of being simple, controllable and suitable for industrialized production with low energy consumption, high efficiency, short reaction time and low cost.

The invention discloses a transition metal oxide/graphene composite material, which consists of a nanometer transition metal oxide and graphene, wherein the transition metal oxide is MnO, Fe2O3, Cr2O3, Cu2O, CuO or V2O5. Because of the dispersing and loading effects of the graphene, the transition metal oxide in the composite material can be distributed uniformly and is small in particle size, and the stability and the cyclical stability of the transition metal oxide in the process of charging and discharging can be effectively improved. The invention also discloses a one-step low-temperature preparation method of the composite material, which has the advantages of simple process, low cost, short cycle, low energy consumption and the like, and is suitable for large-scale industrial production.

The invention discloses a preparation method of a composite lithium metal anode and belongs to the technical field of lithium metal batteries. The preparation method of the composite lithium metal anode comprises steps as follows: firstly, the surface of a framework material is modified, the framework material with the lithiophilic surface is prepared, the framework material is contacted with liquid metal lithium, so that the liquid metal lithium is injected into the framework material with the lithiophilic surface, and the composite lithium metal anode is prepared after cooling. The lithiophilic surface can be obtained through modification of various framework materials (including a conductive framework material and an insulated framework material), the framework materials are efficientlycomposited with the liquid metal lithium, and the composite lithium metal anode material is obtained. When the obtained composite lithium metal anode material is assembled in a total battery, growthof lithium dendrites can be effectively inhibited, the volume expansion effect of the anode is relieved, the pulverization phenomenon of the lithium metal anode is reduced, and the cycling stability and the safety of the lithium metal battery are substantially improved, and the cycle life of the lithium metal battery is substantially prolonged.

The present invention discloses a preparation method of a complex lithium negative pole of a solid state battery, and belongs to the technical field of electrochemistry and new energy resources. The preparation method mainly comprises the steps: depositing lithium metal on three-dimensional carbon material or foam porous material gaps by using a heat infusing melting method or an electrodeposition method to obtain the complex lithium negative pole, wherein the application of a three-dimensional framework plays two roles, namely, providing adequate space for pre-storing lithium in the preparation process; providing a carrier for receiving metal lithium in a battery circulation process. The complex lithium negative pole can be widely applied in lithium metal batteries such as lithium ion batteries, lithium-air batteries, lithium-sulfur batteries, and solid state batteries. In the assembled symmetric solid state battery, under large electric current density of 5mA cm-2, a stable voltage decay (200mV) can still be kept after circulation for 100 times, in the battery circulation, the growth of lithium dendrites can be inhibited and the pole volume change can be stabilized, and the advantages of being good in circulation stability, and long service life can be realized; in the present invention, a carrier material is rich, and low in price; the process is controlled, the cost is low, and the batch production can be realized.

The invention discloses a manganese/lithium phosphate of lithium iron battery positive pole material and a production method thereof, the technical issue to be solved is to improve electrochemical performances of the positive pole material. The material of the invention includes substrates of manganese/lithium phosphate which are covered by a carbon material covering layer, the lithium covering the manganese/lithium phosphate behind the carbon material covering layer is spherical and has microscopic characteristics of being near spherical, rhombic, tapered, tabular, layered or/and block-shaped as well as of having 0.5-30 mum long and short axles. The production method comprises the following steps of: production of nanometer particles, liquid phase mixed reaction, production of precursor, sintering treatment, covering organic substances. Compared with the prior art, the invention improves the electron conductivity of the manganese/lithium phosphate by covering with carbon liquid phase, the carbon sufficiently covers active materials to efficiently prevent particle aggregation, the invention has the characteristics of about 4V of discharge voltage, high discharge and charge capacitance, excellent circulation stability, high safety, simple process, low cost and little influence on the environment.

The invention relates to a synthesis and surface modification method of a lithium rich anode material Li1+xM1-xO2 (M is one or more of Ni, Co and Mn, and X is more than or equal to 0 and less than or equal to 1/3) for a lithium ion battery. The method comprises the following steps of: synthesizing a precursor by using a carbonate precipitation method, mixing the precursor and a lithium salt, and calcining for 2 to 20 hours at the temperature of between 800 and 1,100 EG C to obtain a lithium rich material, wherein the prepared lithium rich material has controllable particle size and higher reversible capacity; and dissolving persulfate or sulfate in an amount which is 5 to 80 mass percent of the lithium rich material into deionized water, adding the lithium rich material, stirring for 2 to 100 hours at the temperature of between 25 and 80 DEG C, heating the materials to the temperature of between 100 and 500 DEG C in a muffle furnace, calcining the materials for 2 to 20 hours, fully filtering the obtained materials, and washing off impurities to obtain the surface modified anode material Li1+x-yM1-xO2. The synthesized lithium rich material has controllable particle size; the first charge/discharge efficiency of the lithium rich material and the discharge specific capacity and the cyclical stability under high magnification can be improved; and the method is simple, low in cost, convenient for operation and suitable for industrialized production.

The invention discloses a lithium ion battery silicon carbide composite anode material and a preparation method thereof and aims to solve the technical problem of improving the cycling stability of a silicon carbide cathode. The lithium ion battery silicon carbide composite anode material consists of the following components in percentage by mass: 85 to 75 percent of graphite and 15 to 25 percent of silica particles, wherein the nano silica particles are dispersed on a graphite carrier to form a nuclear shell structure and are 5 to 16 mum in granularity. The preparation method comprises the following steps of: preparing a graphite dispersing agent and a silicon grinding dispersing agent; adding the silicon grinding dispersing agent into the graphite dispersing agent; and performing thermal treatment. When the method is compared with the prior art, silicon atoms are dispersed on a graphite atomic nucleus by a cation-anion charge absorption method, so that the silicon atoms can uniformly wrap the surface of the graphite, the dispersity of silicon is effectively improved in a silicon carbide composite material preparing process, the initial efficiency and the cycling stability of the silicon carbide composite anode material are improved, and a battery using the material as an anode material has relatively high safety, multiplying power performance and cycle performance.