471 results about "Potassium-ion battery" patented technology

The present invention belongs to the technique field of the battery and the capacitor, and in particular to an asymmetrical water-system sodium / potassium ion battery capacitor. The invention combines an insertion-extraction mechanism of sodium ion or potassium ion in the electrode material and the double electrode layer capacitor mechanism generated by ionic adsorption into an energy storing device. In the energy storing device, the positive electrode adopts the electrode material in which the sodium ion or potassium ion can be inserted and extracted. The negative electrode adopts the porous carbon material of high specific surface area activated carbon, carbon nano-tube, carbon fiber, mesoporous carbon or carbon aerogel and the like. The electrolyte adopts the water solution containing sodium or potassium ion compound. The battery and capacitor of the invention have the advantages of wide material source, easy preparing, low cost, good security, no environmental pollution, long cycle lifetime, higher energy density and power density. The battery and capacitor can be used as the energy source of various electric appliance, and are especially suitable as the electrokinetic cell of the electric car.

The invention provides a siliceous composite material, comprising silicon particles, graphite particles and conducting polymer, wherein, the conducting polymer is wrapped on the surface of the graphite particles; at least part of the silicon particles is adhered to the surface of the conducting polymer. The siliceous composite material provided by the invention takes the conducting polymer as a clad material; the polymer does not need to be transformed further into 'hard carbon' and the siliceous composite material is guaranteed to have excellent conductivity; meanwhile, the aggregation between silicon particles can be avoided. When the composite material is taken as negative active material of a lithium iron battery, the lithium iron battery is guaranteed to have high reversible capacity and good cycle performance. Therefore, the invention can be used as the negative active material of the lithium iron battery. As the polymer does not need to be transformed further into the 'hard carbon' and the siliceous composite material has good conductivity in the preparation of the siliceous composite material provided by the invention, the manufacturing technique is simplified and the problem of huge energy consumption caused by the high temperature carbonization process in the prior art is solved.

The invention discloses a potassium-based dual-ion battery and a preparation method thereof and relates to the field of electrochemical energy storage devices. The potassium-based dual-ion battery comprises a negative electrode, a positive electrode, a membrane between the positive electrode and the negative electrode and an electrolyte, wherein an active material of a negative electrode materialis a porous carbon material capable of reversibly absorbing and desorbing potassium ions; the active material of a positive electrode material is a graphite carbon material capable of reversibly intercalating and deintercalating anions in the electrolyte; and the electrolyte comprises a potassium salt and a non-aqueous solvent. The defects that an existing lithium-ion battery is limited in lithiumresource reserves and high in cost are alleviated, and the problems that an existing potassium-ion battery is limited in electrode material and not ideal in electrochemical properties are solved. According to the dual-ion battery disclosed by the invention, potassium is taken as an energy storage medium, the porous carbon material capable of absorbing and desorbing the potassium ions is taken asa negative active material and expanded graphite capable of being reversibly intercalated and deintercalated is taken as a positive active material, so that the potassium-based dual-ion battery has the advantages of high specific capacity, long cycle life and good security performance.

The invention provides a three-dimensional hollow material, a preparation method thereof, and an application thereof in electrochemical energy storage devices. The three-dimensional hollow material is a self-supporting three-dimensional hollow material obtained through high-temperature carbonization of a foam resin material containing an ether bond under normal-temperature oxygen-free inert atmosphere conditions. The three-dimensional hollow material can be used as an electrode material to form a three-dimensional hollow carbon-based electrode; and the three-dimensional hollow material also can be compounded with a high-specific activity active electrode material to form a composite electrode. The three-dimensional hollow carbon-based electrode and the composite electrode can be applied to the electrochemical energy storage devices. The prepared three-dimensional structure and hollow structure coupled flexible three-dimensional hollow material can be used as an electrochemical energy storage device electrode or current collector. For example, the three-dimensional hollow material can solve the instability problem during intercalation / deintercalation of large ions (such as Na<+> and K<+>) and obtain a high specific capacity and a long life when used as a sodium and potassium ion battery negative electrode.

The invention discloses a positive electrode material for a potassium ion battery and a preparation method thereof, and the potassium ion battery. The positive electrode material has a chemical formula of K<x>P[R(CN)<6>], wherein x is no less than 0 and no more than 2, P is a transition metal ion, and R is Fe<2+> or Fe<3+>. The preparation method comprises the following steps: dissolving potassium ferricyanide or potassium ferrocyanide and a transition metal salt to prepare a uniform solution; then carrying out a hydrothermal reaction; separating a precipitate produced in the hydrothermal reaction; and carrying out washing and vacuum drying so as to obtain the positive electrode material. The preparation method in the invention is simple in process, easy to operate, low in cost for required raw materials and suitable for large-scale industrial production. The prepared positive electrode material has an open three-dimensional network frame structure, and great interstitial sites allow potassium ions to shuttle and to be stored, so the potassium ion battery assembled from the positive electrode material has high discharge capacity, long cycle life, and high energy density and power density.

The invention discloses a lithium ion battery positive electrode material and a preparation method and application. The preparation method of the lithium ion battery positive electrode material comprises the following steps of (1) dissolving a soluble nickel salt, a soluble cobalt salt and a soluble manganese salt in deionized water to obtain a mixed metal ion salt solution with certain concentration, wherein the valence states of nickel, cobalt and manganese in the nickel salt, the cobalt salt and the manganese salt are all right bivalent; (2) adding the mixed metal ion salt solution into a kettle reactor, simultaneously adding a sodium carbonate solution, adding ammonia water again to adjust a pH value to 8-11, controlling a temperature to 55-60 DEG C, performing protection with an inert gas, and performing continuous stirring; (3) filtering a carbonate precursor solution, washing the product with the deionized water, and placing the product a drying oven for drying; and (4) grinding precursor powder, performing pre-sintering, adding anhydrous potassium carbonate, performing mechanical ball-grinding, and performing high-temperature solid-phase sintering to obtain the positive electrode material with a chemical formula K<x>(Ni<y>Co<z>Mn<1-y-z>)O<2>. The preparation method has the advantages of simple operation, short period and low cost.

The invention belongs to the technical field of potassium ion batteries and in particular relates to a potassium / prussian blue secondary battery. The battery is a battery system composed of a prussian blue anode, a metal potassium sheet cathode, an organic electrolyte and a diaphragm. A FeFe(CN)6 electrode material is used for the potassium ion battery, wherein the specific capacity can reach 124mAh / g, the voltage platform is 3.5V, and the energy density can reach 434Wh / kg. The material shows excellent rate capability and circulating stability, and provides a good experimental basis for development of potassium secondary battery anode materials.

The invention belongs to the field of composite materials, and discloses a carbon fiber composite material containing a single-layer MXene nanosheet as well as preparation and application thereof. Thepreparation method comprises the steps of carrying out high-energy ball milling pretreatment and etching treatment on a micron-sized MAX-phase ceramic material to obtain two-dimensional layered MXene, and carrying out ultrasonic stripping to obtain a single-layer MXene nanosheet; mixing the single-layer MXene nanosheet, a soluble high-molecular polymer and an organic solvent to obtain a spinningprecursor solution, carrying out electrostatic spinning, and carrying out pre-oxidation and carbonization treatment to obtain the carbon fiber composite material containing the single-layer MXene nanosheet. The material has unique structural advantages, the obtained single-layer MXene nanosheet can be well embedded into the carbon fiber, the obtained composite material is good in conductivity andlarge in specific surface area, and the potassium ion / electron diffusion path can be effectively shortened. The material has the characteristics of high specific capacity, good long-period cycle performance, excellent rate capability and the like when being applied to a potassium ion battery negative electrode material.

The invention belongs to the field of new energy sources, and particularly relates to a carbon coated SnS2 composite material as well as a preparation method and application thereof. The invention provides the carbon coated SnS2 composite material which has a hollow shell-core structure; the shell is a hollow carbon shell; the inside is SnS2 nanometer sheets; a space gap is reserved between the SnS2 and the hollow carbon shell. The material can be applied to lithium ion batteries or sodium ion batteries or potassium ion batteries when being used as a negative electrode material.

The invention relates to a flexible self-supporting three-dimensional layered MXene / zinc composite electrode and a preparation method and application thereof. The composite material is composed of a three-dimensional layered MXene film and metal zinc, wherein the three-dimensional layered MXene film is composed of one or a mixture of more than two of Ti3C2, Nb4C3, Ti2C, Ta4C3, TiNbC, (V0.5Cr0.5)3C2, V2C, Nb2C, Ti3CN, Ti3C2, Ti2C, Ta4C3, TiNbC, (V0.5Cr0.5)3C2, V2C, Nb2C, Nb4C3 or Ti3CN; and the three-dimensional layered MXene film is loaded with zinc. The flexible self-supporting MXene / zinc composite electrode has larger specific surface area, can load more zinc, can serve as a zinc metal negative electrode or a current collector of a lithium metal negative electrode, can well suppress growth of zinc dendrites or lithium dendrites, and can be used as the negative electrode material of a secondary charge-discharge battery, such as a lithium-ion battery or a sodium-ion battery or a potassium-ion battery, or the electrode material of a supercapacitor.

The invention discloses a prussian blue derivative Fe-Co-Ni sulfide and preparation method and application thereof. The prussian blue derivative Fe-Co-Ni sulfide is of a three-dimensional porous structure and is obtained by vulcanizing Fe-Co-Ni prussian blue, the frame is fixed by carbon, and the prussian blue derivative Fe-Co-Ni sulfide is prepared by a wet chemical method and by subsequent vulcanization and thermal processing. The prussian blue derivative Fe-Co-Ni sulfide has ultrahigh specific capacity, favorable cycle property and excellent rate performance when used as a sodium / potassiumion battery negative electrode. Compared with other sodium / potassium ion battery negative electrode materials, the material has the advantages that the mass specific capacity of the negative electrodematerial can be effectively improved, and the energy density of all batteries is improved; and meanwhile, the preparation method is simple and practical, and industrial production of the sodium / potassium ion battery negative electrode material is expected to be achieved by corresponding development.

The invention discloses a polyanion compound KYi(PO4)3, a preparation method of a carbon coating thereof and application of a product of the polyanion compound KYi(PO4)3 and the polyanion compound KYi(PO4)3 as a potassium ion battery electrode material. The method has the advantages that operation is easy and convenient, a solvothermal method is adopted, and synthesis is easy; the reaction temperature is low, reactions are mild, and the yield is high; raw materials are TiO2, KH2PO4.2H2O, H3PO4 and deionized water with the stable chemical properties, and the cost is low; no harmful gas is generated in the reaction process, and no pollution is caused. Various methods show that the product is uniform in morphology, the phase is pure, and no impurity is generated. The KYi2(PO4)3 and KTi2(PO4)3 / C with the nanoscale cube structures are applied to a potassium ion battery, and tests show that the electrochemical performance of the potassium ion battery is good, and the electrochemical performance of KTi2(PO4)3 / C is better.

The invention provides a novel organic negative electrode material of a potassium ion battery. An active substance of the novel organic negative electrode material is an organic carboxylic potassium salt. A preparation method of the novel organic negative electrode material comprises the steps of firstly performing ultrasonic mixing of a carboxylic acid-containing organic matter and potassium hydroxide; performing sealing reaction for 24-72 hours at 100-120 DEG C, adding a solvent to make the mixture precipitated; and finally, performing centrifuging, washing and drying to obtain the novel organic negative electrode material. The negative electrode material shows a reversible potassium ion de-intercalation platform and excellent cycle performance and is provided with an excellent potassium ion and electron transmission channel, a crystal structure is stable in an electrolyte, the synthesis method is simple, green and environmental-friendly, and a flexible battery can be prepared. By such type of potassium ion battery, the problems of resource shortage of an electrode material of the lithium ion battery, environmental pollution caused by usage of transition metal and the like can be effectively solved.

The invention provides a recycling method of negative electrode material of a waste lithium ion battery, and belongs to the technical field of new battery systems. The recycling method comprises the following steps: disassembling and recycling the negative electrode material of the waste lithium ion battery; after that, washing, drying and calcining the negative electrode material to obtain recycled graphite; and taking the recycled graphite as the negative electrode material, and applying the recycled graphite to a sodium ion battery and a potassium ion battery, so as to realize secondary utilization of the recycled graphite. The recycling method provided by the invention has simple steps, saves resources, and the recycled graphite shows superior electrochemical performance. The result ofthe embodiment of the invention shows that the recycled graphite is applied to the sodium ion battery and the potassium ion battery, after that, the sodium ion battery and the potassium ion battery are high in charging specific capacity and good in cycle performance.

The invention discloses a lithium ion battery negative electrode active material. The negative electrode active material adopts a core-shell structure; the inner core layer of the core-shell structure adopts a carbon source material; the carbon source material is selected from at least one kind of natural spherical graphite, soft carbon and hard carbon; the shell layer of the core-shell structure comprises 1.5-8 parts of amorphous carbon, 5-20 parts of tin-cobalt alloy and 0.5-3 parts of carbon nanotube based on 100 parts of carbon source materials in parts by weight. The invention also provides a preparation method for the lithium ion battery negative electrode active material, a lithium ion battery negative material containing the negative electrode active material, a lithium ion battery negative electrode containing the negative electrode material, and a lithium ion battery containing the negative electrode. The lithium ion battery prepared from the lithium ion battery negative electrode active material with the core-shell structure provided by the invention is high in initial efficiency, specific volumetric capacity, rate capability and cycling stability.

The invention relates to an anode material being suitable for an aqueous metal ion battery and a preparation method for the same. The anode material contains bismuth oxide and is a nano bismuth oxide array thin film, which is formed by oriented growth of bismuth oxide nano sheets on a metal substrate. The bismuth oxide nano sheets are vertically, uniformly and densely distributed on the metal substrate in an array structure, or that bismuth oxide powder is uniformly mixed with a conductive additive and a binder to form a film on the metal substrate. The anode material is suitable for many types of aqueous batteries, including aqueous lithium ion batteries, aqueous sodium ion batteries, aqueous potassium ion batteries, aqueous magnesium ion batteries, aqueous calcium ion batteries, aqueous strontium ion batteries, aqueous barium ion batteries, aqueous aluminum ion batteries, etc. The aqueous metal ion battery based on the anode material has high capacity, good charging / discharging platform, and high electrochemical reversibility.

A sodium or potassium battery is provided, prior to an initial charge and discharge cycle, with a halogen salt additive. As is conventional, the battery is made up of the following components: an anode, a cathode, and an electrolyte. In addition, the battery includes a halogen salt (MX), where M is a metal and X is a halogen element. The halogen salt is added to the anode, the cathode, the electrolyte, or combinations thereof. The concentration MX with respect to the component(s) to which it is added is in the range of 0.01% to 10% in weight. The element X can be selected from the group of halogen elements listed in the Periodic Table. M is a material such as lithium, sodium, potassium, cesium, magnesium, calcium, barium, titanium, manganese, iron, cobalt, nickel, copper, zinc, ammonium, or combinations thereof. Advantageously, the electrolyte may be either aqueous or non-aqueous.

The invention relates to a red phosphorus / nitrogen-doped graphene composite negative electrode material, a method for preparing the same and application of the red phosphorus / nitrogen-doped graphene composite negative electrode material. The method includes uniformly mixing nitrogen-doped graphene and red phosphorus with each other according to a mass ratio of (2-4): (8-6) to obtain mixtures; carrying out ball-milling on the obtained mixtures in protective atmosphere to obtain the red phosphorus / nitrogen-doped graphene composite negative electrode material. The red phosphorus / nitrogen-doped graphene composite negative electrode material, the method and the application have the advantages that nitrogen-doped graphene materials with good electronic conductivity are used as substrate materials, ball-milling is carried out on the nitrogen-doped graphene materials and the red phosphorus, accordingly, insulation red phosphorus particles can be effectively dispersed in the conductive nitrogen-doped graphene materials in ball-milling procedures, the red phosphorus / nitrogen-doped graphene composite negative electrode material which is a composition has large specific surface areas, the integral conductivity can be improved, the contact areas between the red phosphorus / nitrogen-doped graphene composite negative electrode material and electrolyte solution can be increased, the problems ofstructural collapse and pulverization due to volumetric expansion of phosphorus-based material in potassium ion de-intercalation procedures can be solved, and the potassium ion diffusion speeds can be increased; the red phosphorus / nitrogen-doped graphene composite negative electrode material can be used as a negative electrode material for potassium ion batteries and is high in reversible capacity and excellent in rate capability and cycle stability.

The invention discloses hard carbon prepared from biomass waste bagasse as well as a preparation method of the harden carbon and an application of the harden carbon using as a negative electrode material of sodium ion batteries and potassium ion batteries. The preparation method takes the bagasse as a raw material, mechanical ball milling is performed, high-temperature treatment is performed, andtherefore the hard carbon is prepared. The hard carbon provided by the invention exhibits excellent electrochemical performance when being used as the negative electrode of the sodium ion batteries and the potassium ion batteries; at the current density of 50mA / g, the sodium storage specific capacity is still 267.7mAh / g after 200 cycles; and the hard carbon prepared by the method takes the biomasswaste bagasse as the raw material, has low costs, is environmentally friendly, has the simple preparation method and is suitable for large-scale production.

The invention discloses a flame-retardant potassium ion battery electrolyte and a preparation method thereof. The flame-retardant potassium ion battery electrolyte comprises an organic solvent, sylvite and a flame retardant. The organic solvent is a carbonic ester organic solvent and / or an ether organic solvent. The flame retardant accounts for 0.1-50% of total mass of the flame-retardant potassium ion battery electrolyte. The general structural formula of the flame retardant is as shown in the specification, wherein R1-R6 all can be alkyl groups, alkyloxy group, halogenated alkyl group, halogenated alkyloxy group, halogenated alkylene group, phenyl group, biphenyl group, halogenated phenyl group, halogenated biphenyl group, alkyl silicon, alkyloxy silicon, alkyl phosphate, alkyloxy boron or amide group. According to the flame-retardant potassium ion battery electrolyte, safety of a potassium ion battery can be raised, and cycling stability of the battery and battery capacity retention ratio also can be enhanced.

The invention discloses a preparation method of a potassium ion battery positive electrode material potassium vanadium fluorophosphates / carbon. The preparation method comprises the following steps: mixing reaction raw materials and a polyethylene glycol solution to form a viscous solution, drying the mixture, roasting under the condition of high-temperature inert atmosphere and synthesizing the K3V2(PO4)2F3 / C composite material. The reaction solid raw materials are subjected to reaction in the mixing process by utilizing the high solubility characteristic of the polyethylene glycol to form a polyethylene glycol mixed solution dispersed uniformly, so that the defects of long conventional liquid phase reaction time and non-uniform solid phase reaction are overcome, the method is low in timeconsumption and simple in operation, and the synthesized material granules are fine and uniform. Saccharide compounds and the polyethyle glycol are pyrolyzed at high temperature and under inert atmosphere to generate high-conductivity carbon in situ, the surface of the active material is coated with the high-conductivity carbon, agglomeration and growth of the active material granules are prevented, the K3V2(PO4)2F3 / C potassium ion battery positive electrode material with high conductivity is obtained, and the material has excellent electrochemical performance.

The invention discloses a method for using biomass porous carbon as a potassium ion battery cathode. Firstly, a biomass precursor is evenly mixed with specific salt, a pollution-free molten salt carbonization method is adopted to prepare a three-dimensional classification porous carbon material, a carbonization temperature and a ratio of the specific salt to a biomass raw material in a reaction process are regulated and controlled to obtain the porous carbon material, and the porous carbon material is used as the potassium ion battery cathode. The porous carbon cathode material is prepared bya molten salt carbonization method which comprises the following steps that: 1) cleaning and smashing the biomass raw material into precursor powder; 2) carrying out ball milling and mixing on the precursor and the specific salt particles; and 3) after a product in 2) is coated with salt powder, rising the temperature to 500-1200DEG C at a rate of 1-10DEG C / min under air, keeping the temperature for 3-6h, and washing, separating and purifying the generated product to obtain a target product. The synthesis method is simple and is free from pollution, operation steps can be easily controlled, scale production is realized, and realizability is high. The obtained porous carbon material is used as the potassium ion battery cathode and has excellent electrochemical performance and good cycling stability.

A method for preparing carbon-coated zinc sulfide-supported graphene as negative electrode of potassium ion battery belongs to that field of functional nanometer material and electrochemistry. The methanol solution of 2-methimidazole is added dropwise into the methanol solution of zinc nitrate hexahydrate, stirred for a period of time, aged, centrifuged, washed and dried to obtain a ZIF-8 precursor. And then ZIF-8 power and methanol are mixed into solution, adding cysteine, urea and glucose step by step, stirring, transferring to a high-pressure reaction kettle, setting that temperature at 120DEG C and the time is 6-48h, centrifugally cleaning and vacuum drying. Finally, the powders were mixed with the aqueous solution of graphene oxide and dried centrifugally, and then transferred to a tubular furnace for heating and heat preservation in an inert protective atmosphere to obtain carbon fully coated zinc sulfide loaded graphene composites. The negative electrode material of the potassium ion battery prepared by the invention has strong repeatability, simple requirements on the experimental equipment, large specific surface area, high reversible capacity, excellent rate performanceand the like, and has wide application prospects in the fields of catalysis and energy storage.

The invention discloses a self-supporting sodium / potassium ion battery material, a preparation method thereof and an application of the material. The self-supporting sodium / potassium ion battery material is particularly porous sulfur doped graphene aerogel, the content of sulfur is 2-10wt%, and the structure of the material is a three-dimensional structure formed by self-assembling flake graphene.Oxidized graphene water solution firstly reacts with ammonia water and then freeze-dried to obtain graphene aerogel, and the graphene aerogel reacts with sulfur steam at high temperature to obtain the porous sulfur doped graphene aerogel. The porous sulfur doped graphene aerogel is compacted and then used for a sodium / potassium ion battery negative electrode in a self-supporting mode. A sodium / potassium ion battery taking the porous sulfur doped graphene aerogel as the negative electrode has the advantages of ultrahigh specific capacity, excellent cycling performance, good rate and the like.Compared with other non-self-supporting negative electrode materials, the self-supporting material can decrease consumption of current collectors and adhesives and can more easily improve sodium / potassium ion battery performances.

The invention relates to a method for preparing a potassium manganese oxide for a potassium ion battery positive electrode material. The method comprises the following steps: S1, dispersing a manganese source and a potassium source in deionized water, and stirring to form a first solution; S2, adding an oxalic acid solution into the first solution, stirring to obtain a second solution, heating the second solution until the moisture is evaporated to dryness so as to obtain a precipitated material; S3, tabletting the precipitated material, pre-calcining, and cooling after pre-calcining so as to obtain a pre-calcined material; and S4, grinding the pre-calcined material so as to obtain a ground material; tabletting and calcining the ground material, cooling to room temperature after calcining, thereby obtaining the potassium manganese oxide for the potassium ion battery positive electrode material. The method for preparing the potassium manganese oxide for the potassium ion battery positive electrode material provided by the invention is simple in process, low in cost and convenient for realization of large-scale production.

The invention discloses a tellurium-doped MXene composite material and a preparation method thereof. The material comprises the following steps: (1) adding MXene and tellurium source into a dispersantaccording to a mass ratio of 1: 0.01 to 1 to prepare a dispersant with a concentration of 1: 100 mg / ml and stirring for 1-5 hours; (2) heating the dispersant to 100-220 DEG C, performing reaction for10-24 h and cooling to room temperature; (3) centrifuging the product obtained in the step (2), washing with a detergent, and vacuum drying; (4) placing the dried product obtained in the step (3) ina corundum ark, transferring the dried product to a tube furnace, and heating the dried product to 300-500 DEG C under the protection of an inert gas, performing heat preservation for 3-5 h, and cooling to the room temperature to obtain the tellurium-doped MXene composite. The composite material prepared by the invention can be used as the negative electrode of the potassium ion battery, the layerspacing is increased, the ion diffusion channel is optimized, and the electrochemical performance of the potassium ion battery is improved.

The invention provides a high-capacity potassium ion battery negative electrode material and a preparation method and application thereof. A potassium ion battery prepared from a nano SnS2 / graphene composite electrode material can obtain the high reversible specific capacity of 714 mAh / g, and has excellent rate capability and cycle performance. Under the condition that the current density is 500 mA / g, the battery can still give play to the reversible capacity of 483 mA / g; under the condition of 50 circles of circulation at the current density of 250 mA / g, the reversible capacity of 464 mAh / g can still be kept, and the bottleneck problem of low capacity of a conventional potassium ion battery is effectively solved.

The invention relates to a preparation method of a nitrogen-doped hard carbon material. The preparation method of the nitrogen-doped hard carbon material comprises the following steps: (1) carrying out acid pickling on plant resources, and then dipping the plant resources in a nitrogen-source aqueous solution to obtain a preform; and (2) carrying out heat treatment on the preform under a protective atmosphere to obtain the nitrogen-doped hard carbon material. The nitrogen-doped hard carbon material has a porous structure, nitrogen atoms are distributed in the hard carbon material and on the surface of the hard carbon material, the nitrogen content is 1-10wt%, and the specific surface area is smaller than 100 m<2> / g. The nitrogen doped hard carbon material has the characteristics that the capacity is high, the first-time coulombic efficiency is higher than 50%, the cycle performance is good, the rate capability is excellent and the like, the nitrogen-doped hard carbon material is used for the field of potassium ion battery cathode materials, the preparation process is simple, the performance is controllable, and the nitrogen-doped hard carbon material has universality and enlargingcapability.

The invention belongs to the field of potassium ion battery materials, and discloses a one-dimensional porous carbon fiber containing sulfide nano particles as well as a preparation method and an application of the one-dimensional porous carbon fiber. A high-molecular polymer and an energetic substance-containing precursor are added into an organic solvent or deionized water, and ultrasonic stirring and dissolving or uniform dispersing are carried out to obtain a spinning precursor slurry, then a high-molecular nano-fiber thin film is obtained through electrostatic spinning, and next, pre-oxidation and carbonization and vulcanization treatment are sequentially carried out to obtain the one-dimensional porous carbon fiber containing sulfide nano particles. The one-dimensional porous carbonfiber containing the sulfide nano-particles has a porous structure, and meanwhile, the active sites are more, the ion transmission distance is short, the conductivity is high, the infiltration of an electrolyte is highly facilitated, and the one-dimensional porous carbon fiber, used as the negative electrode material of a potassium ion battery, has excellent electrochemical performance.

The invention discloses a negative electrode material for a potassium-ion battery, a preparation method thereof and a negative electrode sheet. The negative electrode material is a hierarchical porouscarbon microsphere material and has a hierarchical porous structure. The hierarchical porous carbon microsphere material is constituted by winding nitrogen-doped porous carbon nanofibers. The preparation method of the negative electrode material for the potassium-ion battery is friendly to environment, simple in process, safe, low in cost and capable of achieving mass preparation. The negative electrode sheet comprises a negative electrode material for a potassium-ion battery. The negative electrode material of the invention has high level of nitrogen doping and hierarchical porous structureat the same time, which not only ensures rapid electron and ion transport, but also provides a large number of interface potassium storage active sites. In addition, the negative electrode material enhances the adsorption capacity of potassium-ion, and greatly improves the specific capacity and rate capacity of potassium storage, thus providing the negative electrode material for the potassium-ionbattery and the negative electrode sheet with high energy density and high power density.