929 results about "LITHIUM PHOSPHATE" patented technology

The invention relates to a method for preparing a lithium iron phosphate / carbon composite material of a lithium ion battery, which belongs to the technical field of lithium ion batteries. The method for preparing the lithium iron phosphate / carbon composite material of the lithium ion battery comprises the following steps of: 1) preparing a suspending graphene-dispersed aqueous solution system, namely, crushing graphite to 1 to 5 microns, adding the crushed graphite into distilled water or purified water, adding 0.1 to 5 percent of surfactant, heating with stirring the mixed solution to 180 to 250 DEG C in a sealing way, performing stirring for 2 to 6 hours and reducing the temperature; 2) crushing lithium iron phosphate to the particle size of 1 to 5 microns, adding the crushed lithium iron phosphate into the distilled water or the purified water, adding with stirring 0.01 to 1 percent of coupling agent, performing uniform stirring, adding the graphene-dispersed aqueous solution, and performing stirring and filtration; and 3) vacuum-drying solid powder obtained by the filtration, and calcinating the dried solid powder for 2 to 12 hours to obtain the graphene-coated lithium iron phosphate cathode material. The method has the advantages of simple process, high material performance, high conductivity, high bulk density, high compacted density and the like.

The invention discloses a method for recovering lithium phosphate from lithium iron phosphate black powder. The method comprises the following steps: mixing black powder recovered from waste lithium iron phosphate batteries with sodium persulfate, and calcining; adding water into the obtained calcined product, dissolving, filtering to obtain water extract A and leaching residues, washing the leaching residues with water, and calcining at high temperature to obtain battery-grade iron phosphate; adding a sodium hydroxide solution into the water extract A, and reacting to obtain a water extract B; adding a trisodium phosphate solution into the water immersion liquid B, fully reacting, performing suction filtration to obtain lithium phosphate and filtrate, and cleaning and drying the lithium phosphate to obtain battery-grade lithium phosphate; and freezing and denitrifying the filtrate to obtain a denitrified solution, and adding the denitrified solution into the sodium hydroxide solution for recycling. The method does not generate wastes, recycles the filtrate in the whole process, theoretically realizes zero loss of the lithium element, prevents the iron element from entering the solution, simplifies the preparation steps of the lithium phosphate, and has the advantages of cost reduction and environmental protection.

The invention discloses a recovery technology for waste lithium iron phosphate batteries, and aims to prepare high-purity iron phosphate and lithium phosphate and comprehensively recover valuable metals such as iron, aluminum and copper in the high-purity iron phosphate and lithium phosphate. The method mainly comprises the following steps that waste lithium iron phosphate battery powder is subjected to oxidizing roasting to obtain roasted battery powder, the roasted battery powder is mixed with phosphoric acid and hydrogen peroxide in different molar ratios, the liquid-solid ratio is adjusted through deionized water, oxidizing leaching is conducted, and lithium-rich liquid and primary leaching residues are obtained; the secondary leaching residues are subjected to phosphoric acid activation, and high-purity iron phosphate dihydrate is obtained after the pH is adjusted; and performing metal ion precipitation on the lithium-rich liquid by adjusting the pH value, and finally performing high-temperature calcination to obtain high-purity lithium phosphate. The method not only realizes efficient leaching and separation of lithium, but also improves the precipitation efficiency of iron phosphate, solves the problems of low metal resource recovery rate and serious process pollution in the prior art, and is suitable for large-scale treatment of waste lithium iron phosphate batteries.

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, the positive pole piece comprises a positive active material layer, and the positive active material layer comprises lithium-containing phosphate of an olivine structure; the electrolyte comprises, by mass, 8-30% of a carboxylic ester solvent, a lithium salt and an unsaturated ester additive, the lithium salt comprises lithium hexafluorophosphate and fluorine-containing lithium sulfimide, the mass content of the fluorine-containing lithium sulfimide in the lithium salt is 18-45%, the mass content of the unsaturated ester additive in the electrolyte is 0.05-5%, and the mass content of the unsaturated ester additive in the electrolyte is 0.05-5%. The unsaturated ester additive comprises one or more of vinylene carbonate, vinylethylene carbonate, allyl ethyl carbonate and a fluoro-carbonate additive; the amount of electrolyte in the battery cell is 2.8 g / Ah to 3.2 g / Ah. According to the invention, rapid charging and use reliability of the single battery can be considered.

The invention discloses a high-stability layered oxide sodium-ion battery positive electrode material and a preparation method thereof.The high-stability layered oxide sodium-ion battery positive electrode material comprises a layered oxide matrix and a surface coating layer, a sodium source, a nickel source, a manganese source, a lithium source and a magnesium source are mixed according to the stoichiometric ratio, a pre-sintered product is heated to 850-950 DEG C at the speed of 0.5-2 DEG C / min to be calcined, and the high-stability layered oxide sodium-ion battery positive electrode material is obtained. The calcined product, lithium phosphate and aluminum nitrate are subjected to ball milling and mixing in a citric acid solution with the pH value of 3-5 according to the mass ratio of 1: (0.005-0.03): (0.002-0.02), and the capacity retention ratio of the battery is larger than or equal to 88% after 500 times of circulation under the voltage range of 2.0-4.0 V and the multiplying power of 0.5 C. The comprehensive protection from the bulk phase to the interface is realized by triple doping and gradient coating, and the cycle life is prolonged by two times. Interlayer spacing expansion and coating layer ion conduction cooperate to reduce polarization, and the applicable temperature range is widened to-30 DEG C to 60 DEG C. Seed crystal induction and segmented sintering ensure batch consistency, and the method is suitable for large-scale production. Cheap Fe / Mn is adopted to replace part of Ni, and the material cost is reduced by 40% compared with similar products.

The invention discloses a mixed ion conductor layer for a lithium metal negative electrode, a preparation method of the mixed ion conductor layer and an all-solid-state battery, and belongs to the technical field of sulfide all-solid-state batteries. The preparation method comprises the following steps: synthesizing a sulfide electrolyte 70 (0.75 Li2S-0.25 P2S5)-30LiI through a liquid phase, introducing graphene oxide and a lithium salt precursor 2, 5-dihydroxy-1, 4-benzene diphosphate in the electrolyte preparation process, and carrying out heat treatment and pressing to obtain a mixed ion conductor layer; the graphene oxide can isolate the sulfide electrolyte layer from the lithium metal negative electrode, interface reaction is avoided, and a special porous and interlayer structure provides a transverse growth space for lithium metal deposition. And meanwhile, the lithium diphosphate-based MOF among the graphene layers ensures the rapid movement of lithium ions, enhances the bulk diffusion of lithium at the negative electrode end, reduces the local current density, plays a role in dredging the distribution of the lithium ions, and remarkably prolongs the cycle life of the sulfide all-solid-state battery.

The invention discloses a method for comprehensively recovering valuable elements from a waste lithium iron phosphate battery material. The method comprises the following steps: carrying out alkali leaching on black powder and / or pole piece materials of the waste lithium iron phosphate batteries, and then carrying out solid-liquid separation to obtain alkali leaching residues and an alkali leaching solution; carrying out acid leaching on the alkaline leaching residues, and then carrying out solid-liquid separation to obtain an iron oxide powder product and an acid leaching solution; the alkali leaching liquid is cooled and crystallized to obtain a sodium phosphate product and crystallization mother liquor, and the crystallization mother liquor can be circularly used for the alkali leaching process; adjusting the pH value of the acid leaching solution, precipitating and separating to obtain a lithium phosphate product and a lithium precipitation mother solution, wherein the lithium precipitation mother solution can be used for preparing a sodium sulfate product. The method can effectively separate iron, phosphorus and lithium products, and is high in recovery rate, simple, short in process, low in cost and suitable for industrial application.

The invention discloses a silicon-carbon composite negative electrode material, a negative electrode plate, a preparation method and application. The silicon-carbon composite negative electrode material is of a double-coating structure and sequentially comprises inner core silicon, a lithium phosphate layer and a fluorine-containing carbon layer from inside to outside, and the mass ratio of the lithium phosphate layer to the inner core silicon is (1-5): 100. When the composite material is applied to a lithium ion battery, the core silicon and the specific double coating layers can improve the fast charging performance and the first effect while optimizing an ion transmission path; a specific double-coating structure can be used as a buffer layer, stress generated by volume expansion of silicon can be released, and pulverization of particles is avoided; and moreover, LiF with high ionic conductivity and higher mechanical strength and an SEI film with more stable regulation and control are formed through reaction with an electrolyte, so that the structural integrity of the material is kept, and the cycle performance of the material is improved.

The invention discloses a ternary positive electrode material, a preparation method thereof and an electrochemical device. The preparation method comprises the following steps: mixing a continuous ternary precursor, a lithium source and an aluminum source, and carrying out first sintering to obtain a first sintered product; the primary sintering product is subjected to secondary sintering and dispersion, a single-crystal base material is obtained, the base material comprises a plurality of primary particles, the average size of the primary particles ranges from 2 micrometers to 3 micrometers, and the median particle size Dv50 of the primary particles ranges from 3 micrometers to 5 micrometers; mixing the matrix material with an aqueous solution of lithium phosphate, and carrying out wet coating to obtain a coated product; and sintering the coated product for the third time, so that the lithium phosphate forms a coating layer on the surface of the matrix material, and the ternary positive electrode material is obtained. According to the invention, through two-parameter control of the average size and the median particle size of the matrix material and simultaneous aluminum element internal doping and lithium phosphate surface coating of the matrix material, the structural stability and the cycle performance of the ternary positive electrode material are improved and the service life of the ternary positive electrode material is prolonged through a synergistic effect.

The invention relates to a method for treating a waste iron phosphate positive electrode material by a phosphoric acid-hydrogen peroxide method matched with a specific complexing agent. The method comprises the following steps: crushing the positive electrode material of the waste lithium iron phosphate battery, adding the crushed positive electrode material into deionized water, and stirring to prepare slurry; heating the slurry, dropwise adding a phosphoric acid-hydrogen peroxide mixed solution and a complexing agent, adding a NaOH solution to adjust the pH value to 3.5, and filtering to obtain a filtrate and a filter cake; adding a NaOH solution into the filtrate, and adjusting the pH value to 10 to obtain lithium phosphate; performing evaporative crystallization on the filter cake to obtain trisodium phosphate; the complexing agent is prepared by adding pentasodium salt of amino trimethylene phosphonic acid, triallyl citrate, epoxysuccinic acid and DMF (Dimethyl Formamide) into a reaction kettle, mixing, adding ammonia water to adjust the pH value to be 10, and distilling to remove the DMF after the reaction is finished. The precipitation rate of Fe reaches up to 99.99%, the leaching rate of Li reaches up to 99.91%, and efficient separation and recycling of lithium and iron are achieved.

The invention provides equipment and a process for leaching battery-grade lithium phosphate by using waste lithium iron phosphate, and relates to the technical field of resource recovery and battery material preparation, the equipment comprises a support frame, a heating seat, a leaching tank, a driving mechanism and a discharging mechanism; the heating base is installed in the middle of the interior of the supporting frame, the leaching tank is installed on the inner wall of the heating base, an installation cover is installed on the top of the leaching tank in a sealed mode, a main material pipe and an auxiliary material pipe are installed on the two sides of the leaching tank respectively, and a discharging pipe is installed at the bottom end of the leaching tank; the driving mechanism comprises a mounting seat and a motor, the mounting seat is fixedly arranged at the inner bottom of the mounting cover, and the motor is mounted at the top of the mounting seat. According to the scheme, caked industrial-grade sodium phosphate or sodium hydroxide can be crushed into fine particles by adopting rotary grinding, and a reagent can be uniformly dispersed into a purification solution by matching with rotary dispersion blanking, so that the pH of a system and the concentration of sodium phosphate are integrally stable, local reaction abnormity is avoided, and more stable preparation of battery-grade lithium phosphate is ensured.

The invention belongs to the technical field of lithium ion battery positive electrode material preparation, and relates to a manganese-based positive electrode of an all-solid-state battery system, a preparation method and application of the manganese-based positive electrode, the general formula of the manganese-based positive electrode is Li < 1 + x > NiyCoyMn3yOz, the preparation method comprises the following steps: S1, grinding and mixing a lithium-rich manganese original material and lithium phosphate in an inert gas protective atmosphere to obtain a precursor mixture; s2, performing high-energy mechanical ball milling on the precursor mixture; s3, collecting the powder subjected to high-energy mechanical ball milling in an inert gas protective atmosphere to obtain a manganese-based positive electrode material; the manganese-based positive electrode material disclosed by the invention realizes mixed arrangement of part of cations and a double-phase synergistic heterostructure, and has high energy density and voltage, and a halide and sulfide-based all-solid-state battery assembled by using the manganese-based positive electrode material shows good cycling stability and rate capability.

The invention belongs to the technical field of electrolyte, and particularly relates to a method for preparing liquid lithium hexafluorophosphate from sodium hexafluorophosphate. The method comprises the following steps: adding a sodium source into a hexafluorophosphoric acid aqueous solution for neutralization reaction to obtain a sodium hexafluorophosphate aqueous solution, then extracting to remove water, drying to obtain a sodium hexafluorophosphate solid, and heating and decomposing the sodium hexafluorophosphate solid to obtain phosphorus pentafluoride gas; the phosphorus pentafluoride gas is not mixed with SO3, POF3, HF and other impurity gases, a complex refining and purifying process is not needed, and the phosphorus pentafluoride gas with the purity exceeding 99.9% can be obtained after simple purification and can be directly used for synthesizing liquid lithium hexafluorophosphate. The method does not generate waste acid, does not need a complicated phosphorus pentafluoride gas purification process, is particularly suitable for the requirements of the lithium battery industry on high-purity electrolyte, and has the remarkable advantages of high product purity, small environmental pollution, low production cost and the like.

The invention discloses a ternary positive electrode material, a preparation method thereof and an electrochemical device, and the preparation method comprises the following steps: mixing a nickel-cobalt-manganese precursor and a lithium source, and carrying out primary sintering to obtain a base material; mixing the base material, lithium aluminum titanium phosphate and water at the temperature of 10-20 DEG C, and carrying out filter pressing to obtain a solid material; the solid material and lithium phosphate are mixed and subjected to secondary sintering, so that a composite coating layer is formed on the surface of the base material, the composite coating layer comprises titanium aluminum lithium phosphate and lithium phosphate, and the ternary positive electrode material is obtained. By means of low-temperature washing and composite coating, the conductivity and cycling stability of the ternary positive electrode material are improved.

The invention relates to a method for preparing lithium dihydrogen phosphate from a lithium-containing solution by using an extraction-reverse extraction technology, an extraction agent adopted in the method comprises a main extraction agent, a synergistic extraction agent and a diluent, the pKa value of the main extraction agent is 2.2-7, the synergistic extraction agent has a P = O group or a cavity diameter of 0.12-0.15 nm, the water solubility of the synergistic extraction agent is less than or equal to 50 mg / L, and the diluent is a diluent. The synergistic extraction factor R of the extraction agent is more than 100, R = Dmix / (D1 + D2), Dmix is the extraction distribution ratio of the main extraction agent to the lithium when the main extraction agent and the synergistic extraction agent are mixed according to the mass ratio of 1: 1-1: 2, D1 is the extraction distribution ratio of the main extraction agent to the lithium, D2 is the extraction distribution ratio of the synergistic extraction agent to the lithium, and the stripping agent is phosphoric acid. According to the method disclosed by the invention, by selecting the main extraction agent and the synergistic extraction agent, on one hand, lithium monohydrogen phosphate and lithium phosphate impurities cannot be generated by reaction when phosphoric acid is adopted for reverse extraction, and on the other hand, higher separation degree on sodium and potassium can be achieved during extraction, so that high-purity lithium dihydrogen phosphate can be efficiently prepared.

The invention relates to the technical field of bioanalytical chemistry, in particular to a method for simultaneously enriching and separating glycopeptides and phosphopeptides by using a bionic hydrophilic adsorbent, which specifically comprises the following steps: step 1, preparing a polyether-ether-ketone (PEEK) framework by using a fused deposition modeling method (FDM); 2, soaking the obtained PEEK framework in an aqueous solution containing dopamine hydrochloride and tris (hydroxymethyl) aminomethane, and carrying out a reaction; step 3, then, adding a mixed solution containing hyaluronic acid methacrylate, vinyl phosphoric acid, N, N-dimethyl bisacrylamide and phenyl-2, 4, 6-trimethylbenzoyl lithium phosphate into the PEEK framework; in the invention, in the aspect of material preparation, a fused deposition modeling method (FDM) is adopted to prepare a polyether-ether-ketone (PEEK) frame, and the material has good mechanical properties and chemical stability and can bear a series of subsequent complex treatment processes without being damaged.

The present invention belongs to the field of lithium ion batteries, and specifically relates to an in-situ preparation method and a recovery method for a solid polymer electrolyte, as well as a lithium ion battery. The preparation method provided by the present invention comprises the following steps: a) loading an electrolyte precursor onto a surface of a battery separator, and then assembling same with a lithium ion battery positive electrode and a lithium ion battery negative electrode, to obtain a semi-finished lithium ion battery product, components of the electrolyte precursor in step a) comprising a polymer monomer, a lithium salt and an initiator, the lithium salt being lithium perchlorate, lithium hexafluorophosphate, lithium difluorophosphate, or the like; b) under heating conditions, performing in-situ polymerization of the electrolyte precursor on the battery separator in the semi-finished lithium ion battery product, to obtain a solid polymer electrolyte loaded on the battery separator. The preparation method provided by the present invention does not require an additional catalyst, and the prepared solid polymer electrolyte can be depolymerized by means of heating, and has good environmental and economic benefits.

The invention discloses a manganese iron oxalate precursor, a lithium manganese iron phosphate material and a preparation method and application of the manganese iron oxalate precursor and the lithium manganese iron phosphate material, and belongs to the technical field of battery materials. The lithium manganese iron phosphate material core layer is prepared by taking the oxalate manganese iron precursor with a specific particle size range, particle size distribution uniformity and a specific structure as a raw material, and meanwhile, the shell layer comprising the ionic conductive agent and carbon is introduced outside the core layer, so that the comprehensive performance of the lithium manganese iron phosphate material can be effectively improved; and thus, the capacity, the cycle performance and the first charge-discharge efficiency of the prepared corresponding secondary battery are improved.

A coated cathode material for lithium-ion batteries is disclosed. Methods and systems are further provided for applying a coating to an active cathode material for use in a lithium-ion battery. In one example, the coated cathode material may include a high-nickel content active cathode material, such as lithium nickel manganese cobalt oxide or lithium nickel aluminum cobalt oxide, coated with a coating including one or more high energy density active materials, such as lithium vanadium fluorophosphate and / or a lithium iron manganese phosphate compound. In some examples, the high-nickel content active cathode material may include greater than or equal to 60% nickel content.

The invention provides a modified lithium cobalt oxide positive electrode material and a preparation method thereof.The modified lithium cobalt oxide positive electrode material is of a core-shell structure and comprises a magnesium-aluminum-doped lithium cobalt oxide core material serving as the core-shell structure and a coating layer formed on the surface of the magnesium-aluminum-doped lithium cobalt oxide core material, and the coating layer is lithium titanium aluminum phosphate, lithium niobate and lithium phosphate; the chemical formula of the lithium titanium aluminum phosphate is Li < 1 + x > Al < x > Ti < 1 + 1-x > (PO4) 3, the chemical formula of the lithium niobate is Li3NbO4, the weight of the coating layer accounts for 0.2-2% of the weight of the modified lithium cobalt oxide positive electrode material, the weight ratio of the lithium titanium aluminum phosphate to the lithium niobate in the coating layer is 1: (0.4-2), and the chemical formula of the magnesium-aluminum doped lithium cobalt oxide core material is LiCo < 1-a-b-c > Mg Al Nb < c > O2. The modified lithium cobalt oxide positive electrode material provided by the invention has better battery performance at high temperature, high voltage and high rate.

A positive electrode active material according to an embodiment of the present invention includes a core particle and a coating layer formed on a surface of the core particle, and the coating layer includes a lithium phosphate compound containing a transition metal, in which a difference between a maximum thickness and a minimum thickness of the coating layer may have a prescribed value. The positive electrode active material may be prepared using different types of solvents that are immiscible with each other. The present invention can provide a lithium secondary battery having improved electrochemical stability and power characteristics.

A battery cell, a battery, and an electric device. The battery cell comprises a positive electrode sheet, a negative electrode sheet, and an electrolyte; the positive electrode sheet comprises a positive electrode active material layer; the positive electrode active material layer comprises a lithium-containing material of an olivine structure; the negative electrode sheet comprises a negative electrode active material layer; the size of the positive electrode active material layer in the length direction of the positive electrode sheet is L1 mm, the size of the positive electrode active material layer in the width direction of the positive electrode sheet is W1 mm, the size of the negative electrode active material layer in the length direction is L2 mm, the size of the negative electrode active material layer in the width direction is W2 mm, 1<(L2-L1) / (W2-W1)≤4, L2 / L1>1, and 500≤L1≤600; the electrolyte comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and based on the total mass of the electrolyte, the ratio of the mass content of the lithium hexafluorophosphate to the mass content of the lithium bis(fluorosulfonyl)imide is greater than 1. The usage reliability of the battery cell can be improved.

The invention provides a method for recovering lithium phosphate from a lithium iron phosphate positive electrode material, which comprises the following steps: carrying out oxidation leaching on the lithium iron phosphate positive electrode material by using an acid solution and an oxidizing agent to obtain a first leaching solution and a first leaching residue; after water is added into the first leaching residues for size mixing, alkali leaching is conducted through sodium hydroxide, second leaching liquid and iron / carbon insoluble residues are obtained, and sodium phosphate crystals are obtained after the second leaching liquid is condensed; carrying out lithium precipitation reaction on the first leaching solution by using the sodium phosphate crystal to obtain lithium phosphate and lithium precipitation residual liquid; the lithium precipitation residual liquid is subjected to concentration and impurity removal, and then is subjected to a bipolar membrane electrodialysis process to obtain an acid solution and sodium hydroxide for reutilization. The invention aims to provide a method for mutually separating lithium, iron and phosphorus aiming at the waste lithium iron phosphate positive electrode material, the method can almost completely recover lithium, iron and phosphorus in the lithium iron phosphate positive electrode material, and the lithium is high in recovery rate and high in purity.

The invention relates to the technical field of solid-state batteries, and discloses a positive electrode material which comprises a positive electrode active material, a first coating layer, a second coating layer and an additive. A positive electrode active material including a ternary oxide; the first coating layer comprises lithium phosphate and is coated on the positive electrode active material; the second coating layer comprises lithium phosphorus sulfur chlorine and is coated on the first coating layer to form a composite positive electrode material; the additive comprises lithium difluorophosphate and lithium bis (fluorosulfonyl) imide which are dissolved in an acetonitrile solution; wherein the additive is uniformly dispersed on the surface of the composite positive electrode material through a spray drying method. Therefore, the side reaction of the positive electrode and the solid electrolyte interface can be effectively inhibited, and the interface impedance is reduced. And meanwhile, the stability of circulation and the structure can be improved. The invention also discloses a preparation method of the positive electrode material, a positive plate and a solid-state battery.

Battery device comprising a thermal insulation element and at least two battery cells arranged along a first direction, wherein the battery cell comprises an electrode assembly and electrolyte solution, the electrode assembly comprising positive electrode plates and negative electrode plates, the positive electrode plate comprising positive current collectors and positive film layers arranged on at least one side of the positive current collectors, the positive film layer comprising lithium phosphate, wherein the negative electrode plate comprises negative current collectors and negative film layers arranged on at least one side of the negative current collector, the negative film layer comprising graphite particles. characterized in that the electrolyte solution comprises fluorosulfonylimide salt, wherein the mass fraction of the fluorosulfonylimide salt in the electrolyte solution is 2% to 12%; wherein the battery cell comprises two first surfaces which are opposite each other along the first direction, wherein the thermal insulation element covers at least one of the two first surfaces and the dimension of the thermal insulation element along the first direction is 0.3 mm to 5 mm.

The invention discloses a method for preparing lithium phosphate with high efficiency and low cost, which comprises the following steps: roasting spodumene concentrate and phosphoric acid, and carrying out slurrying leaching and solid-liquid separation to obtain a lithium dihydrogen phosphate solution; the method comprises the following steps: evaporating and concentrating a lithium dihydrogen phosphate solution, regulating the pH value of the lithium dihydrogen phosphate solution to 7-8 by adopting ammonia water, adding calcium phosphate seed crystals, inducing to remove residual calcium ions and magnesium ions in the solution, and carrying out solid-liquid separation to obtain a phosphate solution containing lithium ions; and then adjusting the pH value back to 11-13 by adopting alkali for lithium precipitation to obtain a lithium phosphate solid, and washing and drying to obtain a battery-grade lithium phosphate product. According to the preparation process of the lithium phosphate, the spodumene is acidized and roasted by adopting phosphoric acid, and pulpified and leached, and calcium ions and magnesium ions in a solution are directly induced by adopting calcium phosphate seed crystals to form crystals to be separated out on the basis of a weakly alkaline condition, so that the process steps are simple and convenient, the subsequent purification procedure is omitted, and the preparation process is more suitable for industrialization; meanwhile, the lithium phosphate product with high purity and high yield can be obtained through the simple and convenient process, the purity can reach 99.5% or above, and the yield can reach 92% or above.

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, an isolating membrane and a negative pole piece, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector, the negative pole piece comprises a negative current collector and a negative active material layer arranged on at least one side of the negative current collector, the positive active material layer comprises lithium-containing phosphate with an olivine structure, the electrolyte comprises a silane-based additive, and the mass content of the silane-based additive in the electrolyte is 0.05-1%; the electrolyte further comprises lithium salt, the lithium salt comprises lithium hexafluorophosphate, the mass content of the lithium hexafluorophosphate in the electrolyte is 8%-12%, and the total mass content of the lithium salt in the electrolyte is 10%-18%. The use reliability of the battery cell can be improved.

The invention discloses a method for improving lithium recovery rate, which comprises the following steps: S1, removing impurities from a lithium source solution, and carrying out solid-liquid separation to obtain waste residue and lithium-containing filtrate; s2, concentrating the lithium-containing filtrate to obtain lithium precipitation mother liquor; s3, treating the lithium precipitation mother liquor by using saturated sodium carbonate, and carrying out solid-liquid separation to obtain a crude lithium carbonate product and primary residual liquid; s4, carrying out carbonization pyrolysis treatment on the primary residual liquid, and carrying out solid-liquid separation to obtain battery-grade lithium carbonate and secondary residual liquid; s5, carrying out phosphoric acid lithium precipitation treatment on the secondary residual liquid, and carrying out solid-liquid separation to obtain solid lithium phosphate; according to the present invention, the sodium carbonate lithium precipitation, the carbonization pyrolysis and the phosphoric acid lithium precipitation are combined to form the three-stage precipitation process, such that the gradient recovery of the lithium is achieved, the comprehensive recovery rate of the lithium is improved, the staged precipitation avoids the inhibition of the impurities (Ca < 2 + > and SO4 < 2->) on the subsequent reaction, and the circulation energy consumption and the lithium loss are reduced.

The invention discloses a positive electrode material, a preparation method and application thereof. The positive electrode material comprises a lithium iron phosphate core body and a lithium aluminum titanium phosphate shell layer coating the surface of the lithium iron phosphate core body, wherein the mass of the lithium aluminum titanium phosphate shell layer is 0.1-0.5 wt% of the mass of the lithium iron phosphate core body. The positive electrode material formed by coating lithium iron phosphate with lithium aluminum titanium phosphate is applied to the lithium ion battery, so that the high-temperature cycling stability of the lithium ion battery is improved, side reaction is inhibited, and capacity fading is delayed; the lithium ion diffusion kinetics is optimized, and the high-rate performance is improved.

The invention relates to a method for preparing lithium phosphate from a lithium-containing solution by using an extraction-reverse extraction technology, an extraction agent adopted in the method comprises a main extraction agent, a synergistic extraction agent and a diluent, the pKa value of the main extraction agent is greater than 12.5, the synergistic extraction agent has a P = O group, a hydroxyl group or a cavity diameter of 0.12-0.15 nm, the water solubility of the synergistic extraction agent is less than or equal to 50 mg / L, the viscosity is less than or equal to 50 mpa.s, and the diluent is a diluent. The synergistic extraction factor R of the extraction agent is more than 100, R = Dmix / (D1 + D2), the Dmix is the extraction distribution ratio of the main extraction agent to lithium when the main extraction agent and the synergistic extraction agent are mixed according to the mass ratio of (1: 1)-(1: 2), the D1 is the extraction distribution ratio of the main extraction agent to lithium, the D2 is the extraction distribution ratio of the synergistic extraction agent to lithium, and the stripping agent is phosphoric acid. According to the method disclosed by the invention, by selecting the main extraction agent and the synergistic extraction agent, on one hand, lithium monohydrogen phosphate and lithium dihydrogen phosphate impurities cannot be generated by reaction when phosphoric acid is adopted for reverse extraction, and on the other hand, sodium and potassium can be separated at a higher degree during extraction, so that high-purity lithium phosphate can be efficiently prepared.