50results about How to "Unit cell volume reduction" patented technology

The invention relates to a preparing method for an aluminium and barium activated lithium iron phosphate positive electrode material, which comprises the following steps of: mixing raw materials of a lithium source, an iron source, a phosphate radical source, an aluminium source and a barium source of the positive electrode material according to proportions of 1 mol of Li to 0.002-0.005 mol of Alto 0.0003 mol of Ba to 1 mol of Fe to 1 mol of P, carrying out high-speed ball milling for 20h at a revolving speed of 200 r/min in an absolute ethyl alcohol medium, drying in the temperature of 105 DEG C to 120 DEG C to obtain a precursor, placing the precursor obtained by drying in a high temperature furnace, and calcining for 24h in the high temperature of 500 DEG C to 750 DEG C at a common pure nitrogen atmosphere, thereby obtaining the aluminium and barium activated lithium iron phosphate positive electrode material of the invention. A small quantity of substituted calcium and barium doped in the obtained material are beneficial to the control of the appearance and the grain size of a product and the obtaining of the stable lithium iron phosphate compound; the crystal lattice of the positive electrode material is activated, thereby increasing diffusion coefficients of lithium ions; the initial discharge capacity of the obtained positive electrode material reaches 155.52mAh/g; a relative lithium electrode potential of a charge-discharge platform of the positive electrode material is about 3.5V; after the initial discharge capacity of the positive electrode material exceeds 164mAh/g and the positive electrode material undergoes 100 times of charge-discharge circulations, the capacity is attenuated by about 3.0%; and compared with the reference embodiment of the undoped LiFePO4, the positive electrode material has the advantages that the specific capacity and the circulation stability are increased greatly; and as the price of the barium is higher than that of lithium by more than a hundred times, the production cost can be reduced by more than ten times.

The invention discloses a method for preparing an antimony and barium activated lithium iron phosphate cathode material. The method comprises the following steps of: mixing a lithium source, an iron source, a phosphate group source, an antimony source and a barium source which serve as raw materials according to the ratio of Li to Sn to Ba to Fe to P of 1:(0.00002-0.00005):(0.0003-0.003):1:1, performing high-speed ball milling in an absolute ethanol medium at the rotating speed of 200r/min for 20 hours, drying at the temperature of between 105 and 120 DEG C, and thus obtaining a precursor; and putting the dried precursor into a high temperature furnace, calcining in a common pure nitrogen atmosphere at the temperature of between 500 and 750 DEG C for 24 hours, and thus obtaining the antimony and barium activated lithium iron phosphate cathode material. A small amount of antimony and barium is doped, so that control over the appearance and the particle size of a product is facilitated, a stable lithium iron phosphate compound is obtained, the crystal lattice of the material is activated, a lithium ion diffusion coefficient is improved, and the specific capacity and the circulating stability of the material are greatly improved.

The invention relates to a preparation method of selenium and barium activated lithium iron phosphate anode materials, which includes mixing raw materials of a lithium source, an iron source, a phosphoric acid root source, a selenium source and a barium source according to the following ratio by mole: 1 part of lithium, 0.00002 to 0.00005 part of selenium, 0.0003 to 0.003 part of barium, 1 part of iron and 1 part of phosphoric acid root, milling the raw materials in an absolute ethyl alcohol medium for 20 hours through a high-speed ball with 200r/mimn rotating speed, drying the raw materials under the temperature between 105 DEG C and 120 DEG C to obtain a precursor, placing the precursor obtained by drying in a high-temperature furnace and conducting high-temperature calcination on the precursor under the temperature between 500 DEG C and 750 DEG C for 24 hours in an atmosphere of common pure nitrogen to obtain the niobium and barium activated lithium iron phosphate anode materials. Due to the fact that a small quantity of selenium and barium is mingled for replacement, appearance and particle diameter of products can be favorably controlled to obtain stable lithium iron phosphate compound. Lattice of the products is activated, diffusion coefficient of lithium ions is improved, and first discharging capacity of obtained materials reaches 160.52mAh/g. Electrode potential of a charging-discharging platform is about 3.5V relative to lithium, initial discharging capacity surpasses 168mAh/g, and the capacity attenuates by about 1.2% after 100 times of charging-discharging circulation. Compared with unmingled LiFePO4 contrast embodiment, specific capacity and circulation stability are greatly improved.

The invention relates to a preparation method of a copper-barium-activated lithium iron phosphate anode material. The preparation method comprises the following steps of: mixing raw materials, such as a lithium source, an iron source, a phosphate radical source, a copper source and a barium source according to a mol ratio of 1 of Li to Cu to Ba to Fe to P of 1: (0.00002-0.00005):0.0003:1:1; performing high-speed ball milling at a rotating speed of 200r/min for 20 hours in an absolute ethyl alcohol medium; drying at 105-120 DEG C to obtain a precursor; and placing the precursor obtained by drying into a high-temperature furnace, and calcining the precursor at 500-750 DEG C for 24 hours in an ordinary pure nitrogen atmosphere to obtain the copper-barium-activated lithium iron phosphate anode material. Because a small amount of substituting copper and barium are doped, the shape and the particle size of the copper-barium-activated lithium iron phosphate anode material can be conveniently controlled to obtain a stable lithium iron phosphate compound, the crystal lattice of the lithium iron phosphate compound is activated, the diffusion coefficient of lithium ions is increased, and the first-time discharge capacity of the obtained material reaches 160.52mAh/g; the electric potential of a charging and discharging platform of the copper-barium-activated lithium iron phosphate anode material relative to a lithium electrode is about 3.5V, the initial discharge capacity is more than 168mAh/g, and after 100 times of charging and discharging circulation, the capacity is approximately attenuated by about 1.2 percent; and compared with a contrast embodiment without doping of LiFePO4, the copper-barium-activated lithium iron phosphate anode material has the advantage that: the specific capacity and the cycle stability are greatly improved.

The invention provides a beryllium-barium activated lithium iron phosphate cathode material which has a general chemical formula of LiBexBay FePO4, wherein, x is in a range of 0.00002 to 0.00005, y is in a range of 0.0003 to 0.003, and the mol ratio of Li, Be, Ba, Fe and P satisfies the following equation: 1 mol Li: 0.000020-0.00005 mol Be: 0.0003-0.003 mol Ba: 1 mol Fe: 1 mol P. Doping of a small amount of substituting beryllium and barium is favorable for controlling the morphology and particle size of a product and for obtaining a stable lithium iron phosphate compound, crystal lattice of the cathode material is activated, the diffusion coefficient of lithium ions is improved, and the initial discharge capacity of the cathode material is up to 160.52 mAh; the charge and discharge platform of the cathode material has a potential of about 3.5 V relative to a lithium electrode and has an initial discharge capacity of more than 168 mAh/g, and the capacity of the charge and discharge platform attenuates about 1.2% after 100 cycles of charge and discharge; compared to undoped LiFePO4 in contrast embodiments, the doped lithium iron phosphate cathode material in the invention has greatly improved specific capacity and cycling stability.

The invention relates to a method for preparing a vanadium and barium activated lithium iron phosphate anode material, which comprises the steps of mixing lithium source raw materials, iron source raw materials, phosphate radical source raw materials, vanadium source raw materials and barium source raw materials in the proportion of 1mol Li: 0.00002-0.00005mol V: 0.0003-0.003mol Ba: 1mol Fe: 1molP prior to ball milling in an absolute ethyl alcohol medium at a high revolution speed of 200r/min for 20h, obtaining a precursor after drying at the temperature ranging from 105 DEG C to 120 DEG C, and placing the obtained precursor by means of drying into a high-temperature furnace prior to being calcinated in an ordinary pure nitrogen atmosphere at the high temperature ranging from 500 DEG C to 750 DEG C for 24h, so that the vanadium and barium activated lithium iron phosphate anode material is obtained. By the aid of a small amount of substituted vanadium and barium which are doped, the shape and the grain size of a product can be controlled beneficially, and a stable lithium iron phosphate compound is obtained, so that crystal lattices of the stable lithium iron phosphate compound are activated, lithium-ion diffusion coefficient is increased, the first discharge capacity is as high as 160.52mAh/g, a charge-discharge platform is about 3.5V relative to a lithium electrode potential, the initial discharge capacity exceeds 168mAh/g, and the capacity is attenuated by about 1.2% after one hundred times of cycle. Compared with an embodiment of undoped LiFePO4, the vanadium and barium activated lithium iron phosphate anode material is higher in specific capacity and cyclical stability.

The invention discloses a method for enhancing the structural compactness of a BaMnO4 material, and belongs to the technical field of high-pressure regulation and control of material compactness. 1.2-31 GPa of pressure is applied to a BaMnO4 sample in a diamond anvil cell under the condition of room temperature to obtain the BaMnO4 material with enhanced compactness. According to the preparation method disclosed by the invention, the cell volume of BaMnO4 can be reduced to 304.85 angstroms to the maximum extent, so that the material compactness of the BaMnO4 is effectively improved. The methodprovided by the invention is simple to operate and good in repeatability, and provides a new direction for application of BaMnO4 in the technical fields of sewage treatment and novel positive electrode active materials.

The invention discloses a calcium and barium activated lithium iron phosphate positive pole material. The general formula of the positive pole material is LiCaxFeyPO4, wherein x=0.002-0.005, y=0.0003-0.003, the mol ratio of Li, Ca, Ba, Fe and P is 1.0:(0.002-0.005):(0.0003-0.003):1:1; as the doping of a small amount of Ca and Ba for substitution, the feature and the particle diameter of a product are effectively controlled, thereby obtaining a stable lithium iron phosphate compound, the crystal lattice of the lithium iron phosphate compound is activated, the lithium ion diffusion coefficient is improved, and the loading capacity achieves 155.52 m A h/g in the first time; a charge-discharge platform relative to lithium electrode potential is around 3.5V, the initial discharge capacity exceeds 164 m A h/g, and the capacity decays around 3.0% after charging and discharging are circled for 100 times; compared with the unmixed LiFePO4 comparing embodiment, the specific capacity and the cyclical stability are greatly improved; and as the price of Ba is over hundreds of times lower than that of Li, the manufacturing cost can be reduced by more than 10 times.

The invention discloses a preparation method of a fluorine and yttrium-doped lithium ferrous silicate composite material for a lithium-ion battery. The method comprises the following steps of (1) preparing a fluorine and yttrium-doped lithium iron silicate precursor; (2) preparing porous graphene; and (3) mechanically mixing the porous graphene with the precursor, mixing evenly in a ball milling manner and then burning in a tube furnace in helium atmosphere to obtain porous graphene-coated fluorine-doped lithium ferrous silicate. According to the prepared lithium ferrous silicate composite material for the lithium-ion battery, lithium ferrous silicate is modified by adopting fluorine and a rare-earth material yttrium, so that the cycling stability of the material is improved; and sinteringcoating is also carried out on the fluorine and yttrium-doped lithium ferrous silicate by adopting the porous graphene, so that the conductivity of the material is further improved. Therefore, when the composite material is applied to the lithium-ion battery, the lithium-ion battery has high specific capacity and relatively long service life.