4992 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.

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 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 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 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 asphalt composite derivative hard carbon material and a preparation method and application thereof, and the preparation method comprises the following steps: step (1), placing biomass raw material powder in an acid pickling solvent for acid pickling, washing to be neutral after acid pickling, and drying to obtain a biomass precursor; (2) mixing the biomass precursor with asphalt to obtain a precursor mixture; and (3) carrying out low-temperature pre-oxidation on the precursor mixture, and then carrying out high-temperature carbonization, so as to obtain the biomass asphalt composite derivative hard carbon material after the high-temperature carbonization is finished. The prepared biomass asphalt composite derivative hard carbon material is used for preparing a sodium ion battery negative electrode. The technical problems that an existing biomass hard carbon material is low in capacity and tap density, difficult in impurity removal and the like can be solved, the biomass hard carbon material can be used for a sodium-ion battery negative electrode, and the sodium storage performance of a sodium-ion battery is improved.

The invention provides an electrolyte for a negative-electrode-free sodium metal battery, a preparation method of the electrolyte and the negative-electrode-free sodium metal battery, and relates to the technical field of sodium ion batteries. The electrolyte is mainly prepared from sodium salt and a weak coordination organic solvent, wherein the concentration of the sodium salt in the electrolyte is 1-2.5 mol / L. According to the electrolyte, through the weak coordination organic solvent and specific sodium salt concentration selection in the electrolyte, more anions can enter the solvation structure of the electrolyte to form the electrolyte with the anion-atmosphere solvation structure, and it is verified that the electrolyte has the advantages that the electrolyte is simple in structure and convenient to use. The electrolyte for the negative-electrode-free sodium metal battery can effectively relieve the problem that an existing high-voltage negative-electrode-free sodium metal battery is short in cycle life.

The invention provides a sodium ion battery, an energy storage device and an energy storage system. The sodium ion battery comprises a positive pole piece, a diaphragm, a negative pole piece and an electrolyte, the negative pole piece comprises a carbon material, the specific surface area of the carbon material is x, the carbon material comprises mesopores, the number percentage of the mesopores in the carbon material is y, and the electrolyte comprises an organic solvent, an electrolyte salt, an organic additive and a sodium salt additive, the organic solvent comprises cyclic carbonate and chain carbonate, the mass fraction of the cyclic carbonate in the electrolyte is a, the mass fraction of the chain carbonate in the electrolyte is b, the mass fraction of the organic additive in the electrolyte is c, and the mass fraction of the sodium salt additive in the electrolyte is d; the sodium ion battery meets the relational expression of 0.4 < = a / y < = 0.8; 0.5 < = a / b < = 1.3; 0.4 < = c / x < = 1.2; and 0.1 < = d / c < = 0.5.

The invention discloses a wide-temperature-range sodium-lithium hybrid energy storage system and a control method thereof. According to the system, the working temperature range of the energy storage system is effectively expanded through sodium-lithium hybrid energy storage; the sodium ion battery unit bears a low-temperature working condition, and the lithium ion battery unit bears a normal-temperature basic load, so that the low-temperature and power characteristics of a sodium battery and the high-energy density advantage of a lithium battery are exerted, and complementation of energy density and temperature adaptability is realized; and the independent bidirectional DC / DC converter is adopted for power coupling, so that the problem of voltage mismatching possibly caused by direct parallel connection is effectively avoided, and the reliability and the control precision of the system are improved. The system has intelligent environment perception and adaptive control capabilities, can adaptively adjust a working mode and a power distribution strategy according to environment conditions, and is high in intelligent degree. The modular design is adopted, system expansion and maintenance are facilitated, and the operation and maintenance cost is reduced.

The invention relates to a self-adaptive cooperative control system and method for a sodium-ion battery energy storage system, and relates to the technical field of energy storage system control. An EMS-BMS-PCS cooperative control module is customized, a three-level architecture dynamically adjusts a voltage threshold value, and the SOC is corrected; the multi-stage active safety protection module comprises battery cell monitoring, fault battery cell ejection, modular battery replacement and three-stage fusing protection; the power grid response module PCS performs high-frequency sampling and supports grid-connected and off-grid switching and AGC / AVC service; the intelligent collaborative optimization engine integrates data to generate a charging and discharging strategy, and early warning is performed 14 days in advance for predictive maintenance; the layered distributed control module is used for realizing battery cell-to-system level management; and the double-ring network communication redundancy module ensures real-time transmission of instructions. According to the invention, the DoD and capacity utilization rate of the sodium-ion battery is improved, and the system economy is enhanced; heat spreading is blocked through multi-stage protection, the maintenance time is shortened, and the safety is improved; millisecond-level response meets the high-order demand of a power grid, predictive maintenance reduces the operation and maintenance cost, and the method is suitable for multiple energy storage scenes.

The invention relates to a sodium ion battery, and belongs to sodium ion batteries. The battery cell of the sodium-ion battery comprises a positive plate, a negative plate and an electrolyte, the active material of the positive plate is carbon-coated aluminum-doped sodium ferric sulfate; the chemical formula of the aluminum-doped sodium ferric sulfate is Na < 2 + 2y > Fe < 2-x-y > Al < x > (SO4) 3, x is more than or equal to 0.01 and less than or equal to 0.05, and y is more than or equal to 0.1 and less than or equal to The particle size of the carbon-coated aluminum-doped sodium ferric sulfate ranges from 50 nm to 100 nm; the weight ratio of a carbon coating layer in the carbon-coated aluminum-doped sodium ferric sulfate is 1%-5%; the active material of the negative plate is carbon-coated sodium titanate; the specific surface area of the carbon-coated sodium titanate is 20 m < 2 > / g to 25 m < 2 > / g; the weight ratio of a carbon coating layer in the carbon-coated sodium titanate is 0.5%-3%. Volume expansion is jointly inhibited through structural stability of positive and negative electrode materials, and the cycle life is prolonged.

The invention relates to the technical field of solid-state battery energy conversion, and discloses a high-safety sodium-ion battery energy conversion method based on a solid-state electrolyte, which comprises the following steps: identifying an interface dynamic mismatch risk time period in a charging and discharging process, and applying micro-amplitude high-frequency acoustic vibration disturbance to a solid-state electrolyte and a sodium negative electrode interface in the time period, sodium ion microscopic distribution is regulated and controlled through the acoustic streaming effect, contact stress is dredged, dendritic crystal early nucleation is inhibited, dynamic reconstruction and optimization of the interface state are achieved, the solid-state sodium-electricity interface is converted into dynamic self-adaption from static mismatch, the ion transmission uniformity is actively maintained through the acoustic streaming effect, and dynamic reconstruction and optimization of the interface state are achieved. And meanwhile, real-time sensing of an interface state and dynamic adjustment of acoustic vibration parameters are realized in combination with an acoustic probing mechanism, so that the interface stability and dendritic crystal inhibition capability are effectively improved, and the energy conversion efficiency and the safety performance of the battery are remarkably enhanced.

The invention belongs to the technical field of sodium-ion batteries, and particularly relates to a preparation method of a coal-based hard carbon material and application of the coal-based hard carbon material in a sodium-ion battery negative electrode. The preparation method of the hard carbon material comprises the following steps: carrying out acid-base chemical heat treatment on a coal-based material to obtain an ash-removed and dried precursor material, and activating the material by water vapor to obtain a target sample with etched micropore inner gaps, and in the subsequent carbonization process, the carbon layer is twisted to form a closed pore structure to obtain the electrode material. According to the invention, the application of the rich-resource coal precursor and the high carbon conversion rate in the sodium ion battery is realized, and the storage capacity of sodium and the cycling stability of the material are effectively improved. The coal-based hard carbon material can be used for preparing a sodium ion battery and has important application value.

The invention provides a composite sodium ferric phosphate positive electrode material, a precursor and a preparation method thereof, and a sodium ion battery, and belongs to the technical field of inorganic material preparation. Amorphous iron hydrogen phosphate is successfully prepared by innovatively adopting a wet chemical method, the amorphous iron hydrogen phosphate precursor is mixed with the sodium salt, the phosphorus source and the carbon source, the composite sodium iron phosphate positive electrode material is prepared through a solid-phase sintering process, and the prepared composite sodium iron phosphate positive electrode material is high in purity, high in compaction density and good in stability. The structure stability is good, and the specific discharge capacity and the rate capability are excellent; by adopting the positive electrode material, the reversible specific capacity and the service life of the sodium-ion battery can be effectively improved, and high-quality sodium-ion battery supply is provided for the field of energy storage.

Disclosed herein are halide-based solid electrolytes with high ionic conductivity for all-solid-state sodium ion batteries. For example, disclosed herein are solid electrolytes comprising: ABCλ-2x-zDx+y, wherein: A is chosen from Li, Na, K, Mg, Ca, Zn, Al, In, Fe, and combinations thereof; B is chosen from Ca, Mg, Zn, In, V, Nb, Ta, Mn, Ti, Zr, Hf, Fe, Co, Ni, Al, Ga, and combinations thereof; C is chosen from F, Cl, Br, I, and combinations thereof; D is chosen from O, S, Se, Te, and combinations thereof; λ is an integer chosen from 4, 5, and 6, such that the solid electrolyte is charge neutral; 0 < x < 1; 0 < z < 2; and 0 < y < 1.

The invention provides a Na / P double-site doped phosphoric acid ferric sodium pyrophosphate / carbon positive electrode active material and a preparation method and application of the Na / P double-site doped phosphoric acid ferric sodium pyrophosphate / carbon positive electrode active material. The material comprises a Na / P double-site doped ferric sodium pyrophosphate base material and a carbon coating layer coating the surface of the base material, the general formula of the base material is Na (4-x) MxFe3 (PO4) 2-y (QO4) y (P2O7), 0 lt, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 X is less than or equal to 0.4, 0lt; y < = 0.2; m is at least one of K, Li, Mg, Ca and Sr, and Q is at least one of Si, Ge, B and S; specific elements are introduced to the Na site and the P site to form a synergistic doping structure, so that the crystal structure and charge distribution are regulated and controlled, and the electrochemical performance of the material is further improved; the material disclosed by the invention is simple and convenient to prepare, wide in raw material source, suitable for electrochemical energy storage systems such as sodium ion batteries and the like, and excellent in rate capability and long in cycle life.

The present invention discloses a formation method for a sodium-ion single battery, which includes constant current charging of the sodium-ion single battery at a charging rate of 0.1C - 0.5C under the condition of 20 - 25°C, and the charging cut-off voltage is V C1 and standing still for 30 - 60 minutes, placing the single battery under the condition of 2 - 10°C for 1 - 2 h, and using voltage V C2 to perform constant voltage charging for 2 - 5 seconds and then standing still for 3 - 8 seconds, standing still for 30 - 60 minutes under the condition of 20 - 25°C, and performing constant current discharging of the sodium-ion single battery at a discharging rate of 0.1C - 0.5C, and the discharging cut-off voltage is V D1、 placing the single battery under the condition of 35 - 55°C for 1 - 2 h, and using voltage V D2 to perform constant voltage discharging for 3 - 6 seconds and standing still for 5 - 8 seconds. The formation method of the sodium-ion single battery significantly changes the performance of the sodium-ion battery, effectively improving the first capacity, charge and discharge efficiency, and cycle life of the sodium-ion battery.

The invention belongs to the technical field of sodium ion batteries, and discloses a multi-coal composite sodium battery hard carbon negative electrode material, a preparation method and an application, three coal raw materials with different characteristics are used as a basis, and the hard carbon material with excellent structure and good performance is prepared by using respective component characteristics, pyrolysis characteristics and structural characteristics of the coal raw materials. The whole preparation method is simple, the large-scale production difficulty is low, no high-pollution chemical reagent is used, the reversible specific capacity reaches up to 350mAh / g when the material is used as a sodium-ion battery negative electrode material, and the material shows ultrahigh rate capability.

The invention discloses a biomass-based sodium ion battery hard carbon material and a preparation method and application thereof, and the preparation method comprises the following steps: uniformly mixing a biomass raw material, an oxidation pore-forming reagent and water to obtain a precursor dispersion liquid, standing and drying the precursor dispersion liquid to obtain a hard carbon precursor, pre-carbonizing the hard carbon precursor at 650-900 DEG C for 1-5 h, and cooling to room temperature to obtain the biomass-based sodium ion battery hard carbon material. And carrying out acid pickling to remove impurities so as to obtain an oxidation pore-forming activated material, carrying out deep carbonization on the oxidation pore-forming activated material at 1150-1450 DEG C for 1-8 hours, and cooling to room temperature, so as to obtain the biomass-based sodium ion battery hard carbon material. The biomass-based sodium-ion battery hard carbon material obtained by the invention has the advantages of high first-circle charge specific capacity, high first-circle discharge specific capacity, high slope capacity, high first-circle coulombic efficiency and high cycle stability.

The invention discloses an oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nano material as well as a preparation method and application thereof, and belongs to the technical field of electrode materials. The preparation method comprises the following steps: mixing a structure regulating agent with tin salt, dropwise adding alkali liquor, stirring, and carrying out suction filtration to obtain Sn6O4 (OH) 4; the preparation method comprises the following steps: adding glucose and polyvinylpyrrolidone into distilled water, stirring to form a uniform solution, adding Sn6O4 (OH) 4 into the uniform solution, stirring, and carrying out ultrasonic and hydrothermal reaction to obtain SnO2 / glucose; and calcining the SnO2 / glucose and a sulfur source in an inert atmosphere to obtain the SnO2 / SnS2 / C nano material modified by oxygen and sulfur double vacancies. The SnO2 / SnS2 / C disclosed by the invention is used for a lithium / sodium ion battery negative electrode, can effectively relieve volume expansion of tin-based oxysulfide and improve the conductivity of an electrode material, and shows high charge-discharge specific capacity, excellent rate capability and high-rate long-cycle stability.

The invention relates to a preparation method of a nickel ion doped modified ferric sodium pyrophosphate positive electrode material, and belongs to the technical field of sodium ion battery positive electrode materials. The nickel ion doped modified ferric sodium pyrophosphate positive electrode material is prepared by adopting an integrated process system of liquid phase uniform mixing, spray granulation and precise segmented calcination. According to the process system, atomic-scale uniform doping of nickel ions and a specific microstructure of a precursor are realized through spray drying, and a plurality of inherent key technical problems of low electronic conductivity, low ion diffusion rate, impurity phase generation and the like of an NFPP material are solved together through a synergistic effect with a subsequent calcining process; furthermore, the discharge capacity of the ferric sodium phosphate pyrophosphate composite material at high rate is improved, so that the battery has relatively high cycling stability.

The invention belongs to the technical field of sodium ion negative electrode material preparation, and particularly relates to a double-layer carbon-coated sodium ion battery hard carbon negative electrode material as well as a preparation method and application thereof. The method comprises the following steps: firstly, dispersing activated carbon powder into a tris (hydroxymethyl) aminomethane hydrochloride buffer solution, and then adding dopamine hydrochloride to carry out self-polymerization reaction, so as to obtain activated carbon powder coated with a first layer of polydopamine; then putting the activated carbon powder into a second layer of carbon source precursor solution, and heating in a water bath to obtain double-layer carbon-coated activated carbon powder; and finally, carrying out heat treatment. The preparation method comprises the following steps: firstly, coating the surface of activated carbon with a first layer of polydopamine by an in-situ polymerization method, then promoting uniform coating of a second layer of carbon source precursor by utilizing strong adhesion of the polydopamine, and carrying out heat treatment to obtain the double-layer carbon-coated hard carbon negative electrode material. The hard carbon negative electrode material can improve the energy density of the current sodium ion battery and accelerate the industrial application of the sodium ion battery.

Provided in the present disclosure are a sodium ion battery, a preparation method for the sodium ion battery, an electrical device and a hard carbon material. The sodium ion battery comprises a negative electrode sheet; the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector; the negative electrode film layer comprises a hard carbon material. On the basis of measurement using the nitrogen adsorption method, the hard carbon material comprises a porous structure, and the porous structure comprises pores having a pore size of 2 nm-8 nm; on the basis of measurement using the nitrogen adsorption method, the pore volume of the pores having a pore size of 2 nm-8 nm is 0.0004 cm3 / g-0.0040 cm3 / g.

The invention discloses sodium ion battery positive electrode slurry, a positive electrode plate and a sodium ion battery. The sodium ion battery positive electrode slurry is prepared from the following materials in percentage by mass: 93-97% of a positive electrode main material; 1%-3% of a binder; 1%-5% of a conductive agent; 0.1%-0.5% of an alkaline regulator; and the positive electrode main material is a mixture of a layered oxide sodium battery positive electrode and a polyanion sodium battery positive electrode. The positive pole piece prepared from the layered oxide and polyanion mixed positive pole material is high in compaction, and the obtained sodium ion battery has excellent first effect, energy density, cycle performance and safety performance. The method is simple to operate, slurry mixing is performed in a low-humidity environment in a manner of neutralizing residual alkali on the surface of the material by adopting maleic anhydride, and the obtained positive electrode slurry is good in viscosity and stability, excellent in dispersion effect and excellent in gel resistance.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a sodium ferric pyrophosphate positive electrode material as well as a preparation method and application thereof. The invention provides a preparation method of a sodium ferric pyrophosphate positive electrode material, which comprises the following steps: (1) mixing an iron source, a sodium source, a phosphorus source and citric acid for the first time, and performing spray drying for the first time to prepare a first precursor with D50 of 10-12 [mu] m; performing secondary mixing on an iron source, a sodium source, a phosphorus source and citric acid, and performing secondary spray drying to prepare a second precursor with D50 of 3-5 microns; the iron source comprises a first iron source with D50 of 1.1-1.8 [mu] m and a second iron source with D50 of 0.3-0.8 [mu] m; the mass ratio of the first iron source to the second iron source is (0.3-0.5): (0.5-0.7); and (2) mixing the first precursor, the second precursor and sodium metaborate, and sintering to obtain the sodium ferric pyrophosphate positive electrode material. After the prepared pyrophosphate ferric phosphate sodium positive electrode material is prepared into a pole piece, the compaction density is proper, and the prepared battery is high in specific capacity and cycle performance.

The invention belongs to the technical field of sodium ion battery hard carbon negative electrode materials, and particularly relates to a phenolic resin asphalt super-crosslinking hard carbon composite active material and a preparation method and application thereof.The preparation method comprises the steps of phenolic resin precursor synthesis, oxidized asphalt precursor synthesis, super-crosslinking reaction and stepped carbonization; the preparation method comprises the following steps: reacting phenol with formaldehyde under the action of a catalyst to obtain a phenolic resin precursor; pre-oxidizing the coated asphalt in an air atmosphere to generate an asphalt precursor; the preparation method comprises the following steps: mixing a phenolic resin precursor with an asphalt precursor, adding an acid catalyst into an organic solvent, and performing reflux heating to form a chemically bonded three-dimensional cross-linked network structure; and sequentially carrying out low-temperature pre-carbonization and high-temperature carbonization in an inert gas atmosphere to obtain a target product, namely the hard carbon composite material. The target product provided by the invention has rich closed pore and multistage through pore structure hard carbon, and the sodium storage capacity of the hard carbon material is effectively improved.

The invention is suitable for the technical field of sodium-ion batteries, and provides a sodium-ion battery health state evaluation method based on multi-modal neural network and physical prior fusion, and the method comprises the steps: carrying out the preprocessing of collected multi-modal time sequence data and operation context information, and carrying out the feature extraction of the preprocessed multi-modal data; a physical prior constraint based on a battery electrochemical mechanism is introduced in the fusion process of the extracted feature vectors, and fused multi-modal feature representation is obtained; the method comprises the following steps: constructing a continuous time dynamic model of sodium ion battery health state degradation, and carrying out time sequence dynamic modeling to obtain a hidden state sequence representing a battery degradation state; and based on the hidden state sequence, outputting a health state point estimation value, a physical agent parameter estimation value and an uncertainty quantification result, and evaluating the health state of the sodium ion battery. Accurate description of the battery degradation process is achieved through continuous time dynamic modeling, and intelligent health state evaluation of the sodium-ion battery in the full life cycle is achieved.

Provided are a sodium compensation material, a preparation method thereof, a positive electrode plate, and a sodium-ion battery. The sodium compensation material includes: a sodium compensation agent NaxCyOzHw, where 1≤x≤3, 1≤y≤6, 1≤z≤7, and 0≤w≤5; and a metal oxide catalyst. The sodium compensation material satisfies C1>C0, where C0 represents a content of a metallic element belonging to the metal oxide catalyst measured by performing a first Energy Dispersive Spectroscopy (EDS) test on a pre-selected region of a surface of the sodium compensation material, C1 represents a content of the metallic element belonging to the metal oxide catalyst measured by performing a second EDS test on the pre-selected region after being melted.

The sodium ion battery comprises a positive electrode and a negative electrode, an active material of the positive electrode comprises a polyanionic sodium storage material, an active material of the negative electrode is hard carbon, the ratio of the capacity of a slope region of the negative electrode to the capacity of the positive electrode is 1.1-1.2, and the working voltage of the negative electrode is 0.1-1.0 V. The NP ratio is limited, the working voltage of the negative electrode is limited in a slope region, sodium ions are mainly adsorbed on the surface, and sodium metallization in micropores is avoided; na < 3 > Ti < 2 > (PO4) < 3 > is added into a positive active material, a sodium source is provided for formation of an SEI film by utilizing a reversible decomposition reaction of Na < 3 > Ti < 2 > (PO4) < 3 > at 2.1 V or above, and a sodium pre-treatment process is not needed; the positive electrode and the negative electrode adopt gradient porosity design, so that the dynamic bottleneck of a high-load electrode is effectively solved.