7576 results about "Sodium-ion battery" 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.

A hard carbon negative electrode material as well as a preparation method therefor and a use thereof. The hard carbon negative electrode material comprises a hard carbon base material, heteroatoms and metal monoatoms, wherein the metal monoatoms are doped into the hard carbon base material by means of the heteroatoms, the heteroatoms comprise at least one of N, P or S, and the metal monoatoms are metal monoatoms that can undergo an alloying reaction with sodium. The metal monoatoms are doped into the hard carbon base material by means of covalent (chemical bond) interactions with other heteroatoms, so that the doping of single atoms is achieved, thereby improving the overall capacity and rate capability of a sodium ion battery at normal temperature, and ensuring the capacity retention rate of the sodium ion battery under a low temperature condition.

The invention provides a sodium ferric pyrophosphate positive electrode material cooperatively doped with anions and cations, a preparation method of the sodium ferric pyrophosphate positive electrode material and a sodium ion battery, and relates to the field of sodium ion batteries. The anion and cation synergistically doped ferric sodium phosphate pyrophosphate positive electrode material comprises an inner core and a coating layer covering the outer surface of the inner core, the inner core comprises ferric sodium phosphate pyrophosphate, the coating layer comprises carbon, the chemical formula of the ferric sodium phosphate pyrophosphate is Na4-2yFe2.91-xQx (PO4) 2-yP2O7Fy, x is more than 0 and less than or equal to 0.3, and y is more than or equal to 0.03 and less than or equal to 0.08; q comprises at least one of Sn, Ni, Cu, Mg and Mn. The introduced Q positive ions and F negative ions can keep the crystal structure of the body material stable, and the positive ions and the negative ions have a synergistic effect, so that the band gap of the positive electrode material is reduced, the state density near the Fermi level of the positive electrode material is increased, the conductivity of the positive electrode material is enhanced, the specific capacity of the positive electrode material is improved, and the rate and the cycle performance are promoted.

The invention discloses a power balance control method and system based on a photovoltaic sodium ion battery energy storage system, and relates to the technical field of intelligent power balance. The battery pack state parameters comprise a battery capacity recession rate, a single battery environment temperature gradient and a voltage balance degree at a single battery environment temperature; calculating the thermal management efficiency of the battery pack based on the battery pack state parameters; when the thermal management efficiency of the battery pack is lower than a preset standard threshold value, calculating the ionic conductivity and the rate value of a single battery in the battery pack; and when the ionic conductivity and the rate value of the single batteries in the battery pack are both lower than the preset values, switching the temperature-lost single batteries into a charging mode. By quantifying the thermal management efficiency, the problem that the sodium ion battery cannot be accurately controlled to be stably located at the proper temperature and voltage by the existing battery power balance control technical means is solved.

The invention provides an efficient and controllable sodium ion battery hard carbon negative electrode chemical sodium pre-treatment method, which comprises the following steps: in an inert atmosphere, dropwise adding an aryl-sodium organic solution on the surface of a hard carbon negative electrode plate, and washing and drying the plate after the aryl-sodium organic solution permeates the hard carbon negative electrode plate. The aryl-sodium solvent is 9-methyl fluorene-sodium, 9, 9-dimethyl fluorene-sodium and derivative sodium thereof. Through hard carbon negative electrode pre-sodium treatment, the loss of active sodium in the first-circle charging and discharging process of the negative electrode is compensated, and the first-circle coulombic efficiency of the negative electrode is improved. The method is simple and convenient to operate, the sodium modification degree of the hard carbon negative electrode is controllable, the reaction safety is high, and large-scale research is easy to realize industrial production. The sodium ion total battery is assembled by matching the pre-sodium hard carbon negative electrode and the sodium vanadium fluorophosphate positive electrode, the initial discharge specific capacity of the total battery is greatly improved, the energy density of the sodium ion battery is favorably improved, and the sodium ion total battery has wide prospects and application value.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a calcium ion doped modified sodium ion positive electrode material and a preparation method thereof, a positive electrode plate and a half battery. The calcium ion doped modified sodium ion positive electrode material comprises a sodium source, a doping source and a precursor, and is characterized in that the chemical general formula of the positive electrode material is Na < 1-x > M < x > Ni Fe Mn < c > O < 2 >, the value range of the doping sources M and x is x < = 0.05, a + b + c = 1, and all elements in the chemical formula meet charge balance. Sodium sites in a layered structure are replaced by calcium ion doping, so that interlayer spacing is enlarged, sodium ion transmission kinetics is enhanced, and adverse phase change is inhibited. The sodium ion positive electrode material shows high specific capacity and excellent cycle stability, the capacity retention ratio is 93.03% after 100 times of cycle charge and discharge at 1C, and the sodium ion positive electrode material has the characteristics of simple preparation, low cost, high specific capacity and excellent cycle performance.

The invention relates to the technical field of sodium ion batteries, in particular to a sodium ion electrolyte, a preparation method thereof and a battery. The sodium ion electrolyte comprises an ester solvent, salts and an additive, wherein the ester solvent comprises chain carboxylic ester, chain carbonic ester and cyclic carbonic ester, and the salt comprises sodium salt. The sodium ion electrolyte provided by the invention has high low-temperature conductivity, not only can improve the low-temperature discharge capacity, but also can improve the low-temperature charging capacity, and can widen the charging window of a conventional commercial sodium battery from 0 DEG C to-30 DEG C.

The invention discloses a preparation method of a sodium ion battery coated hard carbon negative electrode material. The preparation method comprises the following steps: S1, precursor preparation: crushing and sieving a biomass raw material; s2, oxidation treatment: mixing the biomass precursor with an oxidizing agent for oxidation treatment; s3, pre-carbonization: carrying out pre-carbonization treatment on the oxidized precursor; s4, precursor mixing: mixing the pre-carbonized precursor with an activating agent; s5, activating treatment: performing low-temperature activation on the mixed precursor; s6, acid pickling treatment: performing acid pickling on the activated precursor, and performing centrifugal drying; s7, coating treatment: carrying out coating treatment on the dried activated material to obtain a coated activated material; and S8, carbonization treatment: carrying out carbonization treatment on the coated activated material to obtain the sodium-ion battery coated hard carbon negative electrode material. The material has the characteristics of good cycling stability, high reversible specific capacity and excellent processability.

The invention relates to a preparation method and application of a manganese ion doped modified ferric sodium pyrophosphate positive electrode material, and belongs to the technical field of sodium ion battery positive electrodes. The preparation method comprises the following steps: adding a sodium source, a phosphorus source and a carbon source into ethanol, uniformly mixing to form a mixed solution, sequentially adding an iron source and a manganese source into the mixed solution, uniformly mixing to form slurry, and drying the slurry to obtain precursor powder; calcining in a protective atmosphere to obtain a manganese-doped carbon-coated ferric pyrophosphate sodium material; the calcining conditions are as follows: heating to the temperature of 300-350 DEG C at the heating rate of 2-3 DEG C / min, carrying out first-stage constant-temperature calcination for 2-3 hours, heating to the temperature of 500-550 DEG C at the heating rate of 5-8 DEG C / min, and carrying out second-stage constant-temperature calcination for 10-12 hours. By doping the manganese ions, the electronic conductivity and the ion diffusivity of the ferric sodium phosphate pyrophosphate composite material are improved, so that the discharge capacity of the ferric sodium phosphate pyrophosphate composite material at high rate is improved, and the battery has relatively high cycle stability.

The invention provides a sodium ion battery electrolyte additive and a composition thereof, an electrolyte and a sodium ion battery containing the electrolyte. The additive is a fluorine-containing cyclic sulfate compound, the composition comprises fluorine-containing cyclic sulfate and other additives, and the fluorine-containing cyclic sulfate has a structure as shown in a formula (I): # imgabs0 # formula (I); the sodium-ion battery electrolyte comprises an organic solvent, a sodium salt electrolyte, the additive and any one composition of the additive, the sodium-ion battery comprises a positive electrode material, a negative electrode material and any one of the combined electrolyte. As the fluorine-containing additive has a relatively low HOMO energy level, the oxidation resistance of the non-aqueous electrolyte can be improved, and the electrochemical window of the non-aqueous electrolyte is widened; meanwhile, the cyclic sulfate participates in the formation of a negative electrode SEI film, so that the electrode interface is stabilized, and the impedance of the negative electrode surface can be remarkably reduced, thereby reducing the overall impedance of the battery, improving the rate capability and high-temperature performance of the battery, and prolonging the cycle life of the battery.

The invention provides an asphalt-based closed-pore carbon material, a preparation method thereof and a sodium ion battery, the preparation method of the asphalt-based closed-pore carbon material comprises the following steps: S1, pre-oxidizing an asphalt-based carbon source in an oxidizing gas atmosphere at 200-350 DEG C to obtain a pre-oxidized product; s2, carrying out low-temperature carbonization on the pre-oxidized product in an inert atmosphere at 300-800 DEG C to obtain a first precursor; s3, performing gas activation on the first precursor in an activated gas atmosphere to obtain a second precursor; s4, performing chemical activation on the second precursor by adopting a chemical activating agent to obtain a porous carbon material; s5, dipping the porous carbon material in an asphalt solution, and then separating and drying to obtain a blank; and S6, carbonizing the blank under the protection of inert gas to obtain the asphalt-based closed-cell carbon material. The asphalt-based closed-cell carbon material has the advantages of high capacity, high first efficiency and high stable circularity.

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.

The invention provides a sodium-ion battery positive electrode material and a preparation method thereof, a sodium-ion battery and electric equipment, and relates to the field of sodium-ion batteries. The positive electrode material of the sodium ion battery provided by the invention comprises an inner core and a shell, wherein the shell covers the inner core; the chemical formula of the inner core is NaaNixFeyMnzM1-x-y-zO2, wherein a is more than or equal to 0.9 and less than or equal to 1.05, x is more than 0 and less than 1.0, y is more than 0 and less than 1.0, z is more than 0 and less than 1.0, and 1-x-y-z is more than 0 and less than 1; the chemical formula of the shell is NaLarCa1-rO2, wherein r is more than 0 and less than 1; in the inner core, the element M comprises one or more of Al, Mg, Ti, Zr, Y, La, Ca, Zn, Cu, W, Li and B. The sodium-ion battery positive electrode material provided by the invention can reduce residual alkali on the surfaces of particles, can inhibit side reaction with an electrolyte, and improves the performance stability of the positive electrode material.

The invention discloses a uniformity control method and system for sodium-ion battery slurry, and the method comprises the steps: carrying out the data preprocessing according to the collected shear stress, shear rate and viscosity parameters of the slurry, and generating a data set containing a training group and a verification group; continuously training the training group by using a linear regression model, generating a control prediction model and deploying the control prediction model; acquiring real-time shear stress, shear rate and viscosity parameters of the slurry, inputting the real-time shear stress, shear rate and viscosity parameters into the control prediction model, and outputting a slurry rheological property prediction result and an additive prediction result at the next moment; dynamically adjusting the stirring speed and the shearing speed of the slurry according to the slurry rheological property prediction result, and dynamically adjusting the feeding amount and the feeding time of the additive according to the additive prediction result; and carrying out loop iteration until the uniformity of the slurry reaches a preset requirement. According to the uniformity control method for the sodium-ion battery slurry, the uniformity of the active material and the additive in the slurry can be improved, and material particle aggregation is reduced.

The invention belongs to the field of sodium ion batteries, and particularly discloses a positive electrode material and a preparation method and application thereof. The positive electrode material is carbon nitride coated fluorine-doped pyrophosphate sodium manganese iron phosphate, the chemical formula of the positive electrode material is NaaFe3-bMnb (PO4-x) 2F4xP2O7 / C3N4, a is larger than or equal to 3.95 and smaller than or equal to 4.1, b is larger than or equal to 0.3 and smaller than or equal to 2.4, and x is larger than or equal to 0.005 and smaller than or equal to 0.05. The sodium ferromanganese pyrophosphate is subjected to fluorine doping and carbon nitride coating, so that the electronic conductivity and the structural stability of the sodium ferromanganese pyrophosphate can be improved, the capacity of the sodium ferromanganese pyrophosphate can be well exerted, and the capacity and the voltage platform of the sodium-ion battery are improved.

The present disclosure relates to the technical field of sodium-ion batteries, and in particular to an iron-based polyphosphate-type sodium-ion battery positive electrode material, a preparation method therefor and a use thereof. An organic ferrous source, a sodium source, a phosphorus source and a dopant are mixed and then ground until D50 is less than 180 nm, so that the reactivity of the material is improved, a solid-phase reaction is facilitated, and doped high-valence metal elements such as vanadium, niobium, titanium, zirconium and tin can be better doped into lattices of the iron-based polyphosphate-type sodium-ion battery positive electrode material (NFPP), so as to replace the iron site to form lattice defects such as vacancies, thereby improving the ionic conductivity of the material, inhibiting generation of NaFePO4 impurity phase, and improving the capacity and cycling stability of the material.

The invention discloses a sodium ion battery SOC estimation method based on extended Kalman filtering. The method comprises the following steps: acquiring charging and discharging voltage, current and open-circuit voltage OCV data of a sodium battery through an HPPC test and a capacity test; and fitting a function relationship between the OCV and the SOC based on the standing balanced voltage data. And constructing a three-order RC equivalent circuit model, and identifying ohmic resistance, polarization resistance and polarization capacitance parameters in the model through curve fitting. Based on the model, a state vector containing SOC and polarization voltage is defined, and a nonlinear state equation and a terminal voltage observation equation are established. And predicting the state vector and the covariance matrix at the current moment according to the state vector and the covariance matrix at the previous moment by using an extended Kalman filtering algorithm, calculating Kalman gain by combining the actually measured terminal voltage, correcting the prediction result, and updating the SOC estimation value. And through loop iteration, real-time high-precision dynamic estimation of the SOC of the sodium-ion battery is realized. The method provides an efficient and accurate SOC estimation solution for a sodium ion battery management system.

The invention provides a sodium ion battery health state estimation method in an energy storage scene. The method comprises the following steps: establishing a sodium ion battery complete attenuation data set under two working conditions and extracting a plurality of battery degradation characteristics; respectively measuring the correlation between the battery degradation characteristics and the SOH by using three correlation analysis methods, and carrying out preliminary screening on the battery degradation characteristics and the SOH to obtain battery degradation characteristics after preliminary screening; carrying out secondary feature screening by using an integral gradient algorithm, and carrying out interpretability analysis by using a KAN network as an agent model, so as to obtain a feature combination with relatively strong contribution to battery life prediction; and the battery degradation features in the feature combination are sent to a Temporal Residual KAN-LSTM network model for training, and the SOH of the sodium ion battery is estimated, so that high-precision SOH estimation and interpretability of the sodium ion battery are realized.

The invention discloses an asphalt-based hard carbon material as well as a pre-oxidation preparation method and application thereof. Belongs to the technical field of asphalt-based hard carbon materials. The pre-oxidation preparation method comprises the following steps: carrying out primary pre-oxidation treatment on asphalt at 250-400 DEG C in air flow of 50-500mL / min; crushing the obtained primary pre-oxidized asphalt, and then carrying out secondary pre-oxidation treatment at 250-400 DEG C in air flow of 50-500mL / min to obtain secondary pre-oxidized asphalt; and carrying out carbonization treatment on the secondary pre-oxidized asphalt. According to the method, the asphalt can be kept in a solid-phase state to be subjected to efficient and thorough oxidation cross-linking reaction, the production cost is reduced, the obtained asphalt-based hard carbon material has high first coulombic efficiency and high capacity, and powerful support is provided for commercial application of sodium-ion battery negative electrode materials and rapid development of an energy storage technology.

The invention belongs to the technical field of sodium ion battery negative electrode materials, and particularly relates to an amylocellulose composite hard carbon material as well as a preparation method and application thereof. Pre-oxidation and pre-carbonization are carried out step by step, the starch cellulose composite hard carbon material is prepared through low-temperature pre-oxidation, a ball milling method, low-temperature pre-carbonization and a high-temperature pyrolysis method in sequence, the obtained starch cellulose composite hard carbon material is used for preparing the negative electrode of the sodium-ion battery, and then the sodium-ion battery is further constructed. An electrochemical performance test result shows that the obtained sodium ion battery has excellent first-circle coulombic efficiency, cycle performance and rate capability; moreover, the preparation method of the starch cellulose composite hard carbon material is simple to operate, can perform a pre-oxidation process in an air atmosphere, does not need additional oxidation treatment, is environment-friendly, can prevent the starch cellulose composite material from melting and foaming in high-temperature pyrolysis, improves the cycling stability of the material, and is suitable for industrial production.

The invention relates to the technical field of sodium ion battery positive electrode materials, and provides a sodium ion battery layered high-entropy oxide positive electrode material, a preparation method thereof, a positive electrode plate and a sodium ion battery. The chemical general formula of the layered high-entropy oxide positive electrode material provided by the invention is NaxNiaMnbMcO2, wherein M is at least four of Li, Zn, Cu, Mg, Ca, Fe, Al, Co, Y, Ru, Ti, Ir, Sb, Te, Sn and Nb. The positive electrode material provided by the invention is good in structural stability, and can effectively inhibit phase change, so that the cycle stability is improved, and the electrochemical performance of sodium storage is enhanced. According to the invention, the precursor is obtained by adopting a sol-gel method, and then is sintered into a phase by adopting a solid-phase reaction method, so that the obtained positive electrode material is uniform in particle distribution and shows good structural stability, and the obtained positive electrode material is obviously superior to a material prepared by adopting a common high-temperature solid-phase method in the aspects of reversible capacity and electrochemical reversibility.

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.

The invention relates to the technical field of new energy battery management, and discloses a sodium ion battery state-of-charge and state-of-health joint estimation method, which comprises the following steps: acquiring a state equation and an observation equation of a sodium ion battery; initializing a state estimation value, a state covariance, a capacity estimation value and a capacity covariance; performing unscented transformation on the state equation to obtain a plurality of key points and weights; a state equation and an observation equation are utilized to spread key points at the # imgabs0 # moment, the state at the # imgabs1 # moment, an observation nonlinear transmission result, a prediction state, an observation estimation value, a corresponding prediction state covariance and a corresponding prediction observation covariance are obtained, Kalman gain at the # imgabs2 # moment is constructed, and an extended Kalman gain matrix is obtained; presetting an innovation length, calculating a historical observation residual error, and constructing a multi-innovation matrix; and based on the extended Kalman gain matrix, the multi-information matrix and the actual observation value at the # imgabs3 # moment, correcting to obtain the sodium ion battery charge state and the battery health state at the # imgabs4 # moment.

The invention discloses a preparation method of a composite high-entropy hard carbon negative electrode material and a sodium ion battery, and relates to the technical field of electrochemical energy storage materials. Existing doping limit is broken through through'high entropy design ', atomic-scale mixing of five elements and more than five elements is realized, strong structural stability which cannot be realized by traditional binary / ternary doping is achieved, 'molecular anchoring' and'entropy locking 'are completed by combining a pre-assembly technology with stepped carbonization, the problem of pain point of multi-element segregation is solved, and the method is suitable for large-scale industrial production. Sodium storage dynamic and thermodynamic properties of a high-entropy hard carbon precursor and an intermediate are synchronously improved through elaborate combination design of multiple elements and subsequent carbonization process parameter optimization, 'defect-interlayer spacing-pore structure 'triple regulation is realized, and the defect degree of high-entropy hard carbon is reduced through design of a coating process; the prepared composite high-entropy hard carbon negative electrode material shows excellent comprehensive performance in a sodium-ion battery, and especially has obvious advantages in high initial coulombic efficiency, high rate capability and long stability.

The invention discloses a biomass hard carbon negative electrode material and a preparation method and application thereof. According to the method, the waste biomass is used as a raw material, selective dissolution regulation of hemicellulose in plants is realized only through pretreatment of the organic acid with proper concentration under the condition of not damaging natural structures of the plants, and cellulose and lignin components are reserved; the biomass hard carbon negative electrode material with improved performance can be obtained through two-step carbonization and acid-base treatment, so that the assembled sodium ion battery has excellent electrochemical performance, and under the condition that the current density is 50mA / g, the first discharge capacity is 286-345mAh / g, the first coulombic efficiency is 92-95%, and the cycle capacity is stable. The method can be used as a universal strategy for optimizing the electrochemical performance of the biomass hard carbon, the preparation process is low in cost and simple, and large-scale application and production of high-performance sodium ion batteries are facilitated.

The invention provides a hard carbon material and a preparation method thereof, and the preparation method comprises the following steps: (S1) crushing asphalt, and carrying out heat treatment in an oxidizing atmosphere to obtain a pre-oxidized precursor; (S2) uniformly mixing the pre-oxidized precursor with a cross-linking agent I, and carrying out primary cross-linking under inert atmosphere and heating conditions to obtain a cross-linked precursor I; the cross-linking agent I is a polymer of which the side chain contains carboxyl; (S3) uniformly mixing the cross-linked precursor I and a cross-linking agent II, and carrying out secondary cross-linking in an inert atmosphere under a heating condition to obtain a cross-linked precursor II; the cross-linking agent II is a micromolecular aromatic hydrocarbon compound (S4) cross-linking precursor II containing a plurality of anhydrides and / or carboxyl groups, calcining, cooling and grinding in an inert atmosphere to obtain the amorphous sodium ion battery negative electrode material. The negative electrode material obtained by the preparation method disclosed by the invention has the advantages of high capacity, high magnification, low cost, simple preparation process, adjustable disorder degree and high carbon yield, and is a carbon material suitable for large-scale production.

The invention belongs to the technical field of sodium-ion batteries, and relates to sodium-ion battery positive electrode slurry and a preparation method thereof, and the sodium-ion battery positive electrode slurry comprises a positive electrode active material, a conductive agent, a binder, a dispersant, a slurry stabilizer and a solvent; the positive electrode active material is a transition metal layered oxide material, the conductive agent is one or a combination of more of conductive carbon black, ketjen black, conductive graphite and a carbon nanotube, the binder is polyvinylidene fluoride, the dispersant is polyvinylpyrrolidone, the slurry stabilizer is one or a combination of more of iron oxide, aluminum oxide, zirconium oxide and titanium boride, and the positive electrode active material is a positive electrode active material. The solvent is N-methyl pyrrolidone; in the slurry preparation step, a binder and a solvent are mixed and dissolved to prepare a glue solution; adding a conductive agent and a dispersing agent for dispersing to obtain a conductive adhesive; adding a positive active material and a slurry stabilizer, and dispersing to obtain final slurry; the invention can effectively solve the problem of slurry flocculation in the homogenizing process of the sodium ion battery positive electrode material.

The invention discloses a hard carbon material, a preparation method and application thereof and a sodium ion battery. The preparation method of the hard carbon material comprises the following steps: S1, mixing a biomass carbon source and mixed molten salt to obtain a mixture, and carrying out heat treatment on the mixture to obtain porous carbon; the mixed molten salt at least comprises two kinds of molten salt; s2, carrying out surface coating treatment on the porous carbon by adopting a coating agent to obtain a hard carbon precursor; and S3, carrying out carbonization treatment on the hard carbon precursor to obtain the hard carbon material. The obtained hard carbon material has proper pore size distribution, closed pore volume and specific surface area, has excellent electrochemical performance when being applied to the sodium ion battery, and can simultaneously take both high sodium storage capacity and excellent first effect into account. Moreover, the preparation method is low in cost, green and environment-friendly, and large-scale production is easy to realize.

The invention relates to the technical field of sodium ion batteries, in particular to a sodium ferric sulfate positive electrode material and a preparation method and application thereof. The preparation method of the sodium ferric sulfate positive electrode material comprises the following steps: obtaining a carbon foam substrate; weighing raw materials according to the stoichiometric ratio of the sodium ferric sulfate positive electrode material, and adding the raw materials into a solvent to obtain a mixed solution; depositing the mixed solution on a carbon foam substrate by adopting an electrostatic spray deposition method to obtain a precursor film; and sintering the precursor film to obtain the sodium ferric sulfate positive electrode material. According to the preparation method, the carbon foam is adopted as a substrate material, the sodium ferric sulfate precursor is prepared through electrostatic spray deposition, and then the sodium ferric sulfate material is obtained through sintering treatment, so that the specific discharge capacity, the rate capability and the cycle performance of the sodium ferric sulfate material are all remarkably improved.

The invention belongs to the technical field of new energy materials, and particularly relates to a low-sulfur metal cation doped ammonium manganese ferric phosphate precursor, carbon-coated modified sodium manganese ferric pyrophosphate and a preparation method and application thereof. According to the invention, the low-sulfur metal cation doped ammonium manganese ferric phosphate precursor is successfully prepared. A proper amount of phosphoric acid source is added into the prepared metal cation doped ammonium manganese ferric phosphate precursor for treatment, so that the sulfur content of the precursor is remarkably reduced, and the molar ratio of manganese, iron, doped elements and phosphorus elements is regulated and controlled to be slightly smaller than 1. The atomic-scale distribution of elements in the precursor is realized, the tap density is also improved, and the subsequent preparation of a high-performance carbon-coated modified manganese ferric sodium phosphate pyrophosphate material is facilitated. The sodium ion battery constructed based on the material has excellent charge-discharge capacity, capacity retention ratio and cycling stability. In addition, the preparation method of the precursor is simple and convenient to operate and easy to control, and has the advantage of wide application.