19852results about "Positive electrodes" patented technology

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, and the electrode assembly comprises a positive pole piece and a negative pole piece; the positive pole piece comprises a positive pole current collecting part and a positive pole film layer; the positive pole film layer comprises lithium-containing phosphate with an olivine structure; the negative pole piece comprises a negative pole current collecting part and a negative pole film layer, and the negative pole film layer comprises a carbon-based material; the electrolyte comprises a carboxylic ester solvent, a first additive and fluorine-containing lithium sulfimide, and the mass content of the carboxylic ester solvent is 8%-60%; the total mass content of the first additive is 2.5%-10%, the first additive comprises 1, 3-propane sultone with the mass content larger than or equal to 0, an ethylene carbonate derivative with the mass content larger than or equal to 0 and vinylene carbonate with the mass content larger than 0, and the ethylene carbonate derivative comprises a compound shown in the formula A; the mass content of the fluorine-containing lithium sulfimide is 4%-8%. According to the invention, the rapid charging performance and the cycle performance of the battery monomer can be improved. # imgabs0 # formula A

The present invention relates to a solid composite cathode material comprising a ceramic oxide electrolyte material and a lithium electrode material. It was found that the addition of lithium halide to the selected electrolyte and cathode materials strongly enhances the electrochemical performance.

The invention discloses a lithium iron phosphate positive electrode material, a preparation method thereof and a lithium battery, and relates to the technical field of lithium ion batteries. According to the method, the pressing index of the lithium iron phosphate positive electrode material is tested by adopting a specific method, so that the pressing index meets a specific range, meanwhile, the average circularity of larger particles in a Dv50-Dv100 range meets a proper range, the lithium iron phosphate positive electrode material has better particle movement capability, and the particles can move at a higher speed to be rearranged during pressing, so that the particle size of the lithium iron phosphate positive electrode material is reduced, and the quality of the lithium iron phosphate positive electrode material is improved. Therefore, the positive pole piece with high compaction density can be obtained, the charge-discharge capacity of the battery can be improved, and meanwhile, the particles can be prevented from being broken when being pressed, so that the positive pole piece has good anti-pressure capability. By adopting the lithium iron phosphate positive electrode material provided by the invention, the lithium battery has relatively high energy density and capacity retention ratio.

The invention discloses a preparation method of a high-compaction-density lithium iron phosphate material, through grading of large and small particle lithium iron phosphate, optimization of a sintering process and reasonable selection of a carbon source and a titanium dopant, the compaction density and the electrochemical performance of the material are remarkably improved, and the preparation method specifically comprises the following steps: mixing iron phosphate, lithium carbonate, the carbon source and auxiliary materials; the preparation method comprises the following steps: carrying out coarse grinding and fine grinding, respectively preparing large-particle lithium iron phosphate and small-particle lithium iron phosphate (a material A and a material B) by adopting spray drying and high-temperature calcination processes, mixing the material A and the material B according to a ratio, adding auxiliary materials, grinding, further carrying out spray drying, calcining and crushing to obtain a final lithium iron phosphate product, and the maximum compaction density of the prepared material can reach 2.712 g / cm < 3 >. According to the present invention, the maximum 1C discharge specific capacity can achieve 140.5 mAh / g, the maximum 1C 3.2 V discharge platform retention rate is 91.4%, and the prepared lithium ion battery negative electrode material has characteristics of excellent conductivity, high discharge capacity and good cycle stability, and is suitable for power batteries and energy storage batteries.

The present invention relates to a sodium-ion battery material, and specifically relates to a sodium ferric phosphate pyrophosphate composite material, and a preparation process, evaluation method and process optimization method therefor and the use thereof. The sodium ferric phosphate pyrophosphate composite material has a spinel-type NaFePO4 phase; and in an XRD diffraction pattern obtained by subjecting the sodium ferric phosphate pyrophosphate composite material to XRD diffraction using CuKα radiation, there are a characteristic diffraction peak T of sodium ferric phosphate pyrophosphate and a characteristic diffraction peak O of spinel-type NaFePO4 at 2θ of 33.6±0.2° and 32.8±0.2°, respectively, the peak intensities thereof are respectively IT and IO, and the diffraction peak intensity ratio Ir is equal to IT / IO, wherein 6.19≤Ir≤13.

The invention provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a positive pole piece, an isolating membrane, a negative pole piece and electrolyte, and the positive pole piece, the isolating membrane and the negative pole piece are arranged in a laminated manner; the positive pole piece comprises a positive current collector and a positive active 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 layer arranged on at least one side of the negative current collector, and the positive active layer comprises lithium iron phosphate primary particles; the isolating membrane comprises a base membrane and a bonding layer, the bonding layer is of a porous continuous structure, and the bonding layer is at least arranged on one side, facing the positive electrode active layer, of the base membrane; the electrolyte comprises a first solvent, and the first solvent comprises one or more of dimethyl carbonate and linear carboxylic ester. The battery monomer has relatively good cycle performance.

The present disclosure relates to a carbon-based nanomaterial composition that may be formed from a gas mixture and a sulfur powder. The gas mixture may include a carbon based gas, an oxygen gas, and a hydrogen gas. The carbon-based nanomaterial composition may include sulfur doped nanospheres.

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, and the electrode assembly comprises a positive pole piece and a negative pole piece; the positive pole piece comprises lithium-containing phosphate with an olivine structure; the negative pole piece comprises graphite particles; the electrolyte comprises a carboxylic ester solvent and a first additive, the thickness of the single-side negative electrode film layer is 50 microns to 75 microns, and the volume average particle size of the graphite particles is 8.5 microns to 13.5 microns; based on the mass of the electrolyte, the mass content of the carboxylic ester solvent is 8%-60%, the total mass content of the first additive is 3%-10%, the first additive comprises 1, 3-propane sultone with the mass content larger than or equal to 0, an ethylene carbonate derivative with the mass content larger than or equal to 0 and vinylene carbonate with the mass content larger than or equal to 3%, and the ethylene carbonate derivative comprises a compound shown in the formula A. According to the invention, the rapid charging performance and the cycle performance of the battery monomer under high energy density can be improved. # imgabs0 # formula A

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrolyte, a positive pole piece and a negative pole piece, the positive pole piece comprises a positive pole current collecting part and a positive pole film layer located on at least one surface of the positive pole current collecting part and containing a positive pole active material, and the positive pole active material comprises lithium-containing phosphate of an olivine structure; the coating weight of one side of the positive electrode film layer is 200mg / 1540.25 mm < 2 > to 370mg / 1540.25 mm < 2 >, the negative electrode plate comprises a negative electrode current collecting part and a negative electrode film layer which is positioned on at least one surface of the negative electrode current collecting part and contains a negative electrode active material, the negative electrode active material comprises a carbon-based material, the conductivity of the electrolyte is 13-20mS / cm, the battery monomer is subjected to constant-current discharge from a 100% state of charge (0.33 C) to 2.0 V at 25 DEG C, and a discharge platform voltage V1 is 3.19-3.235 V. According to the invention, the fast charging performance, the energy density and the cycle performance of the battery monomer can be improved.

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 and a negative pole piece, the positive pole piece comprises a positive current collector and a positive film layer, the positive film layer comprises a positive active material, the positive active material comprises lithium-containing phosphate of an olivine structure, and the electrolyte is a lithium-containing lithium-containing phosphate of a lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing lithium-containing electrolyte. The resistance of the positive pole piece is 0.1 ohm to 30 ohm, the negative pole piece comprises a negative current collector and a negative film layer, the resistance of the negative pole piece is 0.001 ohm to 0.01 ohm, the electrolyte comprises an organic solvent, the organic solvent comprises a chain ester solvent, and the mass content of the chain ester solvent in the organic solvent is 5% to 75%; the conductivity of the electrolyte at room temperature is 13 mS / cm to 20 mS / cm. The heat production amount of the battery monomer can be reduced, and the use reliability and the cycle performance of the battery monomer can be improved.

The invention provides a battery monomer, a battery device and a power utilization device. Each battery monomer comprises a shell and an electrode assembly in the shell, the electrode assembly comprises a positive pole piece, a negative pole piece and an isolating membrane between the two pole pieces, the positive pole piece comprises a positive current collector and a positive active layer arranged on at least one side of the positive current collector, and the positive active layer comprises a positive active material; the positive electrode active material comprises a nickel-containing lithium transition metal oxide and a lithium-containing phosphate, the molar weight of the Ni element in the nickel-containing lithium transition metal oxide accounts for 70-95% of the total molar weight of the transition metal, the positive electrode active material comprises Ni, Co, Mn, Fe and Li elements, and the ratio of the mass of the Ni element in the positive electrode active material to the sum of the mass of the Fe element and the mass of the Mn element is 0.15-2.

The invention provides a lithium ion secondary battery, a battery device, a power utilization device, a preparation method of a positive electrode active material and a preparation method of a positive electrode plate. The lithium ion secondary battery comprises a positive pole piece, a negative pole piece and an electrolyte, the positive pole piece comprises a positive current collector and a positive film layer arranged on at least one side of the positive current collector, and the positive film layer comprises a positive active material; the positive electrode active material comprises lithium-containing transition metal phosphate particles, at least part of the surfaces of the lithium-containing transition metal phosphate particles are provided with carbon coating materials, and in the tangent plane of the positive electrode film layer in the thickness direction of the pole piece, DA90 of the particles is 1400 nm to 2100 nm; the particle size concentration ratio (DA90-DA10) / DA50 is 1.855-2.375, and DA90, DA50 and DA10 refer to the particle sizes of the corresponding particles when the cumulative area distribution of the particles reaches 90%, 50% and 10% in an area cumulative distribution curve of the particles.

The invention provides a positive electrode, a low-temperature electrolyte, a low-temperature sodium-ion battery and a preparation method and application of the low-temperature sodium-ion battery, and belongs to the technical field of battery materials. The low-temperature sodium ion battery comprises a positive electrode, a negative electrode and a low-temperature electrolyte, wherein the positive electrode comprises a positive electrode active material, a binder, sodium salt containing fluorine and sulfur and conductive carbon; the positive electrode is improved by adding sodium salt containing fluorine and sulfur, sulfur / fluorine rich in anion derivatives can be formed on a contact interface of the positive electrode and an electrolyte to form a firm SEI film, the internal resistance of the battery is further reduced, and the coulombic efficiency of the battery during charging and discharging at normal and low temperatures is improved. The low-temperature electrolyte comprises an ester solvent and an ether additive, by adding the ether solvent, the physicochemical property of the electrolyte and the composition of an SEI film on a contact interface of an electrode and the electrolyte are optimized, the viscosity of the electrolyte at low temperature is reduced, the ionic conductivity is improved, and formation of the SEI film rich in sodium fluoride on the surface of a negative electrode can be promoted; and thus, the problem of low coulombic efficiency of battery charge-discharge cycle at low temperature is solved.

A positive electrode plate includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, where the positive electrode active material layer includes a first positive electrode active material represented by chemical formula (1) and a second positive electrode active material represented by chemical formula (2): Li1+xAaFeyMnzTivPO4−wSw (1), and Li2+rNasM1+qO2+t (2); and the positive electrode plate satisfies: 5.2≤R / Q≤13.5. Such a positive electrode plate can achieve a high specific discharge capacity of the electrochemical apparatus, thereby increasing energy density of the electrochemical apparatus. In addition, a relationship between compacted density R and single surface density Q of the positive electrode plate is limited, effectively improving cycling stability and rate performance of the electrochemical apparatus.

A positive electrode plate includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, where the positive electrode active material layer includes two respective positive electrode active materials represented by chemical formula (1) and chemical formula (2): Li1+xNaaCo1+yAlzMgpTiuMvO2+w (1), where in chemical formula (1), M includes at least one of Zr, La, or Y, −0.1<x<0.1, 0<a<0.005, −0.05<y<0.05, 0.01<z<0.05, 0.001<p<0.01, 0<u<0.005, 0<v<0.005, and −0.05<w<0.05; and Li2+rNasN1+qO2+t (2), where in chemical formula (2), −0.2<r<0.2, 0≤s≤0.05, −0.1<q<0.1, −0.05<t<0.05, and N includes at least one of Ni, Cu, Mn, Fe, or Co. Such a positive electrode plate can achieve a high specific discharge capacity of the electrochemical apparatus, thereby increasing high-temperature cycling performance and energy density of the electrochemical apparatus.

The invention discloses a lithium manganese iron phosphate positive electrode material with a core-shell structure, which is prepared by the following steps: mixing a manganese source, an iron source, a phosphorus source, lithium carbonate and a carbon source, grinding and drying to prepare a pre-sintered material; then carrying out gas crushing on the pre-sintered material to obtain a pre-gas crushed material, and carrying out heat preservation at the temperature of 200-600 DEG C; putting the pre-gas crushed material subjected to heat preservation into an iron salt solution for quenching reaction to obtain iron compound coated lithium manganese iron phosphate; and finally, mixing the lithium iron manganese phosphate coated with the iron compound, a lithium source, a phosphorus source and a carbon source, grinding, drying, and carrying out secondary calcination to obtain the lithium iron manganese phosphate material with the core-shell structure. During preparation of the lithium manganese iron phosphate positive electrode material, a lithium manganese iron phosphate pre-sintered body and an iron salt solution are subjected to a quenching reaction to form an iron compound coated lithium manganese iron phosphate pre-sintered body, and then the iron compound coated lithium manganese iron phosphate pre-sintered body and other raw materials of lithium iron phosphate are subjected to a secondary calcination reaction to generate the composite positive electrode material with a core-shell structure. A coating structure is formed, the reaction between manganese and electrolyte is reduced, the dissolution of manganese is inhibited, the Gingtaler effect of manganese is relieved, and the stability of the material is improved; and the material has the advantages of high energy density, high power density, excellent cycle performance and strong core-shell interface bonding force.

The invention provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrode assembly, wherein the electrode assembly comprises a positive plate, a negative plate and a non-aqueous electrolyte; the positive plate comprises a positive current collector and a positive film layer, and the negative plate comprises a negative current collector and a negative film layer; the positive electrode film layer comprises a positive electrode active material, and the positive electrode active material comprises a lithium manganese iron phosphate material and a nickel cobalt lithium manganate material; in the nickel cobalt lithium manganate material, the molar ratio of Ni in the sum of the three elements of Ni, Co and Mn is 0.5-0.95; the non-aqueous electrolyte comprises vinylene carbonate, and the mass content of the vinylene carbonate in the non-aqueous electrolyte is 0.5%-2%; the non-aqueous electrolyte comprises at least one of linear carbonic ester and linear carboxylic ester, and the conductivity of the non-aqueous electrolyte is 9-14 mS / cm. The energy density, the cycle performance and the power performance of the battery monomer are improved at the same time.

Embodiments described herein relate to electrochemical cells with dendrite prevention mechanisms. In some aspects, an electrochemical cell can include an anode disposed on an anode current collector, a cathode disposed on a cathode current collector, the cathode having a first thickness at a proximal end of the cathode and a second thickness at a distal end of the cathode, the second thickness greater than the first thickness, a first separator disposed on the anode, a second separator disposed on the cathode, an interlayer disposed between the first separator and the second separator, the interlayer including electroactive material and having a proximal end and a distal end, and a power source electrically connected to the proximal end of the cathode and the proximal end of the interlayer, the power source configured to maintain a voltage difference between the cathode and the interlayer below a threshold value.

A secondary battery and an electric device. The secondary battery comprises a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, the negative electrode sheet comprises a negative electrode active material layer, and the negative electrode active material layer comprises a negative electrode active material. The coating weight of the positive electrode active material layer is Wz, the coating weight of the negative electrode active material layer is Wf, and Wz and Wf satisfy: 1.6Wf≤Wz≤2.2Wf and 3.25mg / cm2≤Wf≤5.84mg / cm2. Dv99 of the positive electrode active material is 27 μm to 33 μm, and Dv99 of the negative electrode active material is 23 μm to 28 μm. The separator comprises a separator substrate, a first bonding coating, and a second bonding coating, wherein the first bonding coating comprises a first polymer binder, the average particle size of the first polymer binder is 0.3 μm to 3 μm, the second bonding coating comprises a second polymer binder, and the average particle size of the second polymer binder is 10 μm to 38 μm. By means of the configurations, the cycle performance and high-temperature stability of the secondary battery can be improved.

A lithium secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode includes a positive electrode active material layer having a positive electrode active material containing an overlithiated manganese-based oxide represented by Formula 1 below, and the negative electrode includes a negative electrode active material layer having a silicon-based negative electrode active materialLiaNibCocMndMeO2  [Formula 1]wherein, M is at least one selected from the group consisting of Al, B, Co, W, Mg, V, Ti, Zn, Ga, In, Ru, Nb, Sn, Sr, and Zr, and 1≤a, 0≤b≤0.5, 0≤c≤0.1, 0.5≤d<1.0, and 0≤e≤0.2, and. Preferably, in the Formula 1, 1.1≤a≤1.5, 0.1≤b≤0.4, 0≤c≤0.05, 0.5≤d≤0.80, and 0≤e≤0.1.

The invention provides a lithium manganese iron phosphate battery. The battery comprises a positive pole piece, a negative pole piece and a non-aqueous electrolyte, the positive pole piece comprises a positive active material and a positive active coating arranged on at least one surface of the positive active material; the positive electrode active material comprises lithium manganese iron phosphate LiMnxFe1-xPO4 coated with a carbon coating layer, and x is more than or equal to 0.5 and less than or equal to 0.8; the negative pole piece comprises a negative active material and a negative active coating arranged on at least one surface of the negative active material; the battery satisfies the following relational expressions: 4.5 < = (a / 20 + d) / (b + c) < = 12.8; a is a coated diaphragm resistor of the positive pole piece; b is the compaction density of the positive pole piece; c is the mass percentage content of vinylene carbonate in the positive electrode slurry; and d is the mass percentage content of the lithium bis (fluorosulfonyl) imide in the non-aqueous electrolyte. By optimizing the composition of the lithium ion battery, the low-temperature discharge performance of the battery is improved, and meanwhile, the high-temperature cycle performance is considered.

The present disclosure relates to the field of sodium-ion battery technology, and specifically, to a method for preparing carbon-coated sodium iron fluorophosphate from waste lithium iron phosphate and the application thereof. The method for preparing carbon-coated sodium iron fluorophosphate from waste lithium iron phosphate includes: mixing a waste lithium iron phosphate material with an alkaline solution for reaction, followed by solid-liquid separation, to obtain an aluminum-containing filtrate and a lithium iron phosphate filter residue; mixing the lithium iron phosphate filter residue, aluminum chloride and sodium chloride uniformly, followed by vacuum calcination, to obtain a calcination material; and mixing the calcination material with at least one of a sodium source, an iron source and a phosphorus source uniformly to obtain a mixture to which a fluorine source, a carbon source and a solvent are added for uniformly mixing, followed by drying and calcination sequentially to obtain the carbon-coated sodium iron fluorophosphate. The method has the advantages of low costs, a high added value, a short process, and a high recovery rate, and the carbon-coated sodium iron fluorophosphate obtained from the method has excellent electrochemical performance.

Provided are a lithium manganese iron phosphate material and a preparation method therefor, a positive electrode sheet, and a lithium ion battery. The lithium manganese iron phosphate material comprises a core and a coating layer that coats the surface of the core. The chemical formula of the material of the core is LiaMnbFecMdPO4, wherein M comprises at least one element among magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum. The coating layer is formed by sintering a carbon source, and the carbon coating layer comprises graphitized carbon.

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrode assembly, the electrode assembly comprises a positive pole piece, the positive pole piece comprises a positive pole film layer, a positive pole current collecting part and a positive pole lug, the positive pole film layer is arranged on at least one side of the positive pole current collecting part along the thickness direction of the positive pole piece, and the positive pole lug is arranged on the positive pole piece. The positive pole lug is arranged on at least one side of the positive pole current collecting part along the first direction, the positive pole film layer comprises a positive pole active material, the positive pole active material comprises a lithium-containing material with an olivine structure, the single-side coating weight of the positive pole film layer is 200 mg / 1540.25 mm < 2 > to 400 mg / 1540.25 mm < 2 >, and the single-side coating weight of the positive pole film layer is 100 mg / 1540.25 mm < 2 > along the second direction. The distance between a first point of the positive pole current collecting part and the positive pole lug closest to the first point is smaller than or equal to 300mm, the first point is any point of the positive pole current collecting part, and the first direction, the second direction and the thickness direction of the positive pole piece are vertical in pairs. The risk of lithium precipitation of the battery cell can be reduced, and the use reliability of the battery cell is improved.

The invention discloses a molybdenum disulfide and lithium-lanthanum-niobium-oxygen co-coated lithium-rich manganese-based positive electrode material and a preparation method thereof, and realizes double uniform coating of molybdenum disulfide and lithium-lanthanum-niobium-oxygen on the surface of the lithium-rich manganese-based positive electrode material by combining freeze drying and calcining technologies. The double coating layer not only can be used as a stable protective layer to prevent the positive electrode material from being eroded, but also can form a stable coating structure by utilizing the physical and electrochemical compatibility between two adjacent elements of molybdenum and niobium in the same period, so that the electrochemical performance is optimized, the'deoxidation 'phenomenon is avoided, and the service life of the positive electrode material is prolonged. Under co-coating of the molybdenum disulfide and the lithium lanthanum niobium oxide, the lithium-rich manganese-based positive electrode material co-coated with the molybdenum disulfide and the lithium lanthanum niobium oxide is obtained, and the lithium-rich manganese-based positive electrode material co-coated with the molybdenum disulfide and the lithium lanthanum niobium oxide can guarantee the first effect and the specific capacity of the battery and can fully optimize the cycle performance of the battery.

The invention relates to the technical field of solid-state batteries, in particular to oxyhalide solid-state electrolyte as well as a preparation method and application thereof. The method comprises the following steps: taking molten salt LiaMbXc as a raw material, reacting with an oxide AdOf in a molten state, removing steam impurities by utilizing a high-temperature vacuumizing mode, and cooling to prepare the oxyhalide solid electrolyte; according to the invention, the molten salt raw material is molten at high temperature to form the ion melt, and the oxygen element is introduced to replace part of halogen, so that the hardness of the target electrolyte is reduced after cooling, the deformability at room temperature is improved, and the obtained electrolyte is high in conductivity and wide in antioxidant electrochemical window. The prepared oxyhalide solid electrolyte is used for preparing a positive electrode, the adhesion force between the electrolyte and positive electrode material particles, the actual microscopic contact area and the ion migration rate are improved through melt permeation, the problem of a positive electrode interface is effectively relieved, and the electrochemical performance of an all-solid-state battery is improved.

The invention relates to the technical field of battery positive electrode materials, and provides a lithium iron phosphate positive electrode material and a preparation method thereof. The lithium iron phosphate positive electrode material has the characteristic of high energy density, the proportion of iron phosphide impurities in the total mass of the lithium iron phosphate positive electrode material is 0.001-0.008 PPM, the compaction density under the pressure of 3T is 2.68-2.8 g / cm < 3 >, the powder resistivity is 8-15 omega.cm, the 0.1 C discharge capacity is 161-163 mAh / g, the 0.1 C charge-discharge efficiency is 98.5-100%, and the 1C discharge capacity is 145-148 mAh / g. The preparation process is simple and safe, low in cost and high in stability. The content of iron phosphide impurities in a final lithium iron phosphate product can be regulated and controlled by regulating and controlling the phosphorus-iron ratio of the iron phosphate precursor and the ratio of the carbon source to the iron phosphate precursor in two-time burdening and controlling the sintering temperature in cooperation with secondary sintering, and the high-energy-density lithium iron phosphate positive electrode material is obtained.

The invention discloses a gradient composite coated modified lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials. An LMFP precursor is pretreated through a citric acid-ethanol mixed solution, an active crystal face is exposed, and then a three-dimensional gradient coating structure of a polydopamine (PDA) chemical bonding layer, an MXene nanosheet middle layer and a polyaniline (PANI) conductive outer layer is sequentially constructed on the surface of the material, so that the electronic conductivity of the lithium manganese iron phosphate positive electrode material is increased to 10 <-3 > S / cm magnitude, and the performance of the lithium manganese iron phosphate positive electrode material is improved. The capacity retention ratio (1C) of 500 cycles is larger than 90%, the coating layer is not prone to falling off, and meanwhile dissolution of manganese ions is effectively inhibited.

The invention provides a wide-temperature-range chargeable and dischargeable semi-solid-state battery, a preparation method thereof and electric equipment, and relates to the technical field of new energy. According to the wide-temperature-range chargeable and dischargeable semi-solid-state battery provided by the invention, the solid-state electrolyte is added into the positive electrode material, and the diaphragm is coated with the solid-state electrolyte layer, so that atomic-scale contact between the solid-state electrolyte and the surfaces of electrode material particles is fully realized, and the thermal stability of the battery is greatly improved; meanwhile, the problem of slow reaction kinetics at low temperature is solved by using the nano solid electrolyte blended positive electrode material, and the low-temperature cycle performance of the battery is improved; the nanometer solid electrolyte coating diaphragm can solve the problem of poor electrolyte capacity diving, the electrolyte injection coefficient is effectively reduced, meanwhile, low internal resistance is achieved, and the long cycle stability of the battery is further improved; and a coating layer can be formed on the surface of the material by using the coating type binder, so that the side reaction between the electrode material and an electrolyte is effectively reduced, and the dissolution of transition metal Fe ions is remarkably inhibited.

The invention discloses a method for regenerating waste lithium iron phosphate into a lithium manganese iron phosphate positive electrode material under assistance of element doping. According to the method, the waste lithium iron phosphate is successfully regenerated into the lithium manganese iron phosphate material with excellent performance through solid-phase sintering and element doping. Compared with a traditional repairing and regenerating method, the method has the advantages that upgrading and regenerating of the waste lithium iron phosphate are realized, and the market competitiveness of regenerated products is improved. Compared with other methods, the method does not need an acid leaching step, and the recovery process is simpler and more environment-friendly. And an element doping modification means is introduced, so that the performance of the regenerated lithium manganese iron phosphate material is further improved. The invention aims to provide a green, efficient and high-valued method for upgrading and regenerating the waste lithium iron phosphate positive electrode material into the lithium iron manganese phosphate positive electrode material with industrial application prospects.