276 results about "MXenes" patented technology

Disclosed herein are electrochemical cells comprising electrodes prepared from layered materials comprising a substantially two-dimensional ordered array of cells having an empirical formula of M_n+1X_n, where M comprises a transition metal selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, a Group VIB metal, and any combination thereof, X is C_xN_y wherein x+y=n, and n is equal to 1, 2, or 3. Also disclosed herein are batteries comprising the electrochemical cells and methods for electrochemically preparing MXene compositions with the use of the electrochemical cells.

The invention provides an oxide-pillared MXene composite material and an application thereof. The composite material comprises a two-dimensional layered MXene carrier and an oxide loaded between MXene layers. The preparation method comprises the following steps of (1) processing a taken MAX material with an HF acid solution to obtain an MXene material; (2) soaking the MXene material obtained in the step (1) into a solution containing a cationic surfactant, and then carrying out centrifuging, washing and drying to obtain a pre-pillared MXene material; and (3) adding the pre-pillared MXene material to an oxide precursor solution, carrying out centrifuging, washing and drying and carrying out calcination treatment under a protective atmosphere to obtain the oxide-pillared MXene material. The invention provides an application of the oxide-pillared MXene composite material as a negative electrode material of a lithium-ion battery; the capacity of the negative electrode material of the lithium-ion battery can be greatly improved; and the cycle performance is good, so that high capacity and continuous charge-discharge capacity under high current density are met.

The invention relates to a method for preparing a carbon nanoparticle/two-dimensional layered titanium carbide composite material. The method includes the steps that a two-dimensional layered titanium carbide nano material MXene (Ti3C2/Ti2C) is prepared through hydrofluoric acid corrosion; the material MXene (Ti3C2/Ti2C) and monosaccharide are processed through ultrasonic treatment, vacuum impregnation, hydrothermal treatment and other steps, so carbon nanoparticles are generated between layers and on the surface of the MXene (Ti3C2/Ti2C) material, and the carbon nanoparticle/two-dimensional layered titanium carbide composite material is obtained. Raw materials which are not toxic and easy to obtain are adopted, the preparation process is simple, the technology is controllable, cost is low, repeatability is good, the layered structure of the prepared two-dimensional layered MXene (Ti3C2/Ti2C) is uniform and complete, the carbon nanoparticles are evenly distributed between the layers and on the surface of the MXene (Ti3C2/Ti2C) material, and the prepared composite material has the advantages of being large in specific surface area, good in conductivity, good in hydrophilic property and the like and can be used in the fields such as functional ceramic, wave-absorbing materials, supercapacitors and ion batteries.

The invention discloses a preparation method of a carbon nanotube-MXene composite three-dimensional porous carbon material. According to the preparation method of the material, based on the hydrophilic property of the MXene material, the MXene material is dispersed in a carbon nanotube stabilizing solution, and then is added into a PVA water solution to form a uniformly dispersed stable system. The three-dimensional porous composite carbon material is obtained through freeze drying and carbonization. According to the preparation method, a carbon nanotube can be inserted into a two-dimensionallayer structure of MXene, so that sheet agglomeration is prevented. The specific surface area is increased, and the ion migration space is enlarged. The improvement of the unit capacity and the cycling stability is facilitated. The problem that an MXene material and a graphene material are not easy to disperse uniformly is solved. The mesoporous and macroporous composite three-dimensional porous carbon material is prepared. The preparation method is simple, green, environment-friendly, low in cost, high in yield and easy for industrial production.

The invention discloses an MXene-based flexible composite negative electrode material and a preparation method thereof. According to the MXene-based flexible composite negative electrode material andthe preparation method thereof, a transition metal sulfide is loaded on a two-dimensional layered structure of the MXene material through a hydrothermal method. The agglomeration effect of the MXene material is overcome, and the collapse of a layered structure is prevented. Meanwhile, the energy density of the composite material is improved. The MXene material with high conductivity acts as a three-dimensional conductive network skeleton, so that the conductivity and the mechanical strength of the composite material are enhanced. The volume expansion of the transition metal polysulfide material in the charging process is buffered. Meanwhile, the material has good charge-discharge cycle stability. The composite material and expanded graphite are combined to prepare a self-supporting high-flexibility negative electrode material. In the charging and discharging process, the hydrophilic MXene material has high affinity to polysulfides. The electrochemical performance and the capacitive deionization performance of the composite negative electrode material can be further improved. Sulfides generated by transition metal sulfides are eliminated. The shuttle effect of the polysulfides is limited, and the service life of the negative electrode material is prolonged.

The invention provides a two-dimensional slice material enhanced metal-based composite. According to the composite, metal is adopted as a base body, two-dimensional transition metal carbide or carbonitride, namely, MXenes is adopted as a reinforced phase, and MXenes particles are evenly dispersed in metal base body particles. Due to the fact that the MXenes material comprises a hollow carbon position and tends to metallicity, the metal base body has good wettability, and the interface bonding strength of the metal-based composite can be effectively improved. Therefore, the mechanical performance, wear resistance and other performance of the metal-based composite are enhanced. Meanwhile, the electronic coupling effect of the MXenes material and a metal base body interface is better, and the problem that in the prior art, the mechanical performance and corrosion resistance of the metal-based composite are improved through the reinforced phase, and meanwhile the heat conducting and electrical conducting performance of the metal-based composite is reduced can be avoided.

The invention relates to the field of aerogel and electromagnetic absorbing materials, in particular to a preparation method of MXene/cellulose composite aerogel. The preparation method includes the steps that firstly, MAX phase ceramic powder is added into a mixed water solution of lithium fluoride, hydrochloric acid and hydrofluoric acid in a certain proportion for etching to obtain MXene nano-powder; a cellulose sol method is adopted, cellulose powder is added into a mixed water solution of sodium hydroxide and urea in a certain proportion, and a transparent cellulose mixed solution is prepared by cooling the mixture to -12 DEG C; the temperature is maintained, the MXene nano-powder is added into the cellulose mixed solution, and then the appropriate amount of epichlorohydrin is added to the mixture and the mixture is stirred thoroughly for chemical crosslinking; the temperature is raised, and the obtained homogeneous mixture is subjected to a gel reaction; and a gel product is frozen directionally and then freeze-dried to obtain the MXene/cellulose composite aerogel. The composite aerogel has the characteristics of low density, high porosity, good absorbing performance, wide absorbing frequency band and the like, and is convenient to use and suitable for large-scale application in the aerospace field.

The invention provides an Mxene-coated composite electrode material and a preparation method therefor. The preparation method comprises the following steps of (1) adding an electrode material into a solvent to be stirred uniformly, and then adding Mxene to be stirred to obtain a uniform mixed solution; (2) performing spraying granulation on the obtained mixed solution by a spray dryer to obtain Mxene-coated electrode material powder; and (3) performing sintering on the obtained composite electrode material powder under inert gas protection, and then performing cooling. By adoption of the spraydrying method to enable Mxene to coat the electrode material, and by virtue of Mxene, contact between an electrolyte and the electrode material can be blocked, and ion dissolving in the electrolyte and a self-discharge effect can be lowered; in addition, the Mxene is uniformly distributed among the electrode material particles, so that gaps among the electrode material particles can be reduced and the conductivity of the electrode material can be reinforced; and the method is simple in operation, low in cost and the production efficiency can be improved.

The invention provides a preparation method of a tin dioxide/two-dimensional nano titanium carbide composite material. The preparation method comprises: carrying out ball milling on ternary layered Ti3AlC2 ceramic powder; immersing the obtained product in hydrofluoric acid solution to perform the reaction for 6h to 120h; stirring, centrifugally cleaning a corrosion product by using deionized water, and drying an obtained solid sample to obtain a two-dimensional layered nano material MXene-Ti3C2; and mixing SnCl4.5H2O, glucose and the two-dimensional nano MXene-Ti3C2, using ethanol as a solvent, adjusting PH to 12 to 14, stirring with a magnetic force for 2h, performing the reaction at 120 DEG C for 6h, and after naturally cooling to a room temperature, carrying out centrifuging and drying to obtain a SnO2/MXene-Ti3C2 composite material. The material obtained by the preparation method can effectively alleviate a volume effect of SnO2 nano particles, and the SnO2/MXene-Ti3C2 nano composite material has an excellent application prospect in the field of an anode material field of a high storage germanium lithium ion battery.

The invention discloses a mechanically-enhanced electromagnetic shielding film and a preparation method thereof. The electromagnetic shielding film is composed of a few-layer MXene and cellulose nanofibers. In the preparation method of the electromagnetic shielding film provided by the invention, strong oxidizing agents such as HF are not involved, the reaction process is gentle, the process is safe, and the obtained product has good uniformity; the prepared electromagnetic shielding film can withstand up to a tensile stress with 135.3 MPa in a tensile test, and the deformation quantity reaches 16.7%; the electromagnetic shielding film can withstand maximum 14260 bending, shows ultra-high conductivity of 739.4 S/m in a conductivity test, and can reach electromagnetic shielding performanceof 23.8 dB at an ultra-thin thickness of 47[mu]m; and in addition, the electromagnetic shielding film prepared by the method has wide sources of raw materials, low price, safety and environmental protection, and is beneficial to industrialized promotion and application.

The invention relates to an ultrasound-assistant preparation method of layered Mxene-Ti3C2. The method comprises the following steps: (1) Ti3AlC2-MAX phase ceramic powder and an HF solution are mixed, and then dimethyl sulfoxide is added in order to obtain mixed liquor; (2) ultrasonic treatment of the mixed liquor is carried out, and after ultrasonic treatment is completed, a stirring reaction is carried out in an oil bath condition; ultrasonic treatment and the stirring reaction are alternatively and repeatedly carried out, and after the reaction ends, a middle solution is obtained; (3) washing and centrifugation of the middle solution are carried out by using deionized water till pH of supernatant is equal to 5-6; ethanol is used continuously in order to carry out washing and centrifugation, a sediment is obtained, drying treatment is carried out, and layered Mxene-Ti3C2 is obtained. Preparation and layering of Mxene-Ti3C2 are realized simultaneously.

The invention provides an MXene fiber and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing two-dimensional layered MXene dispersion liquid with single-layer graphene oxide dispersion liquid so as to obtain mixed dispersion liquid; and preparing an MXene-graphene oxide composite fiber by using a wet spinning process, and heating and reducing the MXene-graphene oxide composite fiber in a reducing agent so as to obtain a continuous MXene-reduced graphene oxide composite fiber. The prepared MXene-reduced graphene oxide composite fiber has good electrical conductivity and good toughness, can be braided to form MXene-reduced graphene oxide fiber cloth or be blended with other fibers for braiding of a variety of fabrics, and is applicable to thefields of energy devices like flexible supercapacitors and lithium batteries, composite materials, catalysis materials, electromagnetic shielding materials, wave-absorbing materials, etc.

The invention provides a nano metal oxide/MXene heterostructure composite material and a preparation method thereof. According to the nano metal oxide/MXene heterostructure composite material, nano metal oxide is adsorbed on the surface of lamella MXene through van der waals force and evenly dispersed on a lamella base material to form the composite material of an integrated structure; metal oxideparticles with the size as 5 to 100nm occupies 10 to 90% of the total mass of the composite material; the nano metal oxide is one or several of TiO2, SnO2, Fe3O4, RuO2 and MnO2; the nano metal oxideis in a shape of one or several of a nanorod shape, a nanowire shape and a quantum dot shape. According to the nano metal oxide/MXene heterostructure composite material disclosed by the invention, thenano metal oxide is evenly dispersed on the MXene lamella, morphology is regular, a proportion is adjustable, and material conductivity is remarkably improved; the preparation method has the advantages of simpleness, lower cost and large-scale preparation; when being applied to lithium ion batteries or super capacitor composite materials, the nano metal oxide/MXene heterostructure composite material has excellent cycling performance and rate capability.

The invention provides a sulfur-doped MXene material which is of a layered structure; the specific surface area of the material is 30m<2>/g to 70m<2>/g; and based on atomic percentage, the sulfur atom doping amount in the sulfur-doped MXene material is 1% or above. The invention also provides a preparation method of the sulfur-doped MXene material and an application by adopting the sulfur-doped MXene material as an electrode material of a supercapacitor and a lithium ion battery. By virtue of the sulfur-doped MXene material provided by the invention, the specific capacity and cycling stability of MXene used as the electrode material are improved; and in addition, the preparation method is simple, the doping content of the sulfur element is controllable, and large-scale development and application can be realized.

The invention discloses a two-dimensional metal carbonitride derived nano-material and a preparation method therefor. The derived nano-material has a chemical composition represented as AMO, wherein Ais alkali metal, M is a transition metal element in an MXene precursor, and O is an oxygen element; and the derived nano-material has a sea-urchin-shaped microsphere structure, a porous network structure or a nano-wire microsphere structure, and ultrathin nano-ribbons or ultrafine nano-wires serve as basic structural units of the derived nano-material. The preparation method for the derived nano-material comprises the steps of treating a dense layered ternary metal carbide (MAX phase) material with an etching agent so as to prepare accordion-shaped two-dimensional MXene, and then, carrying out oxidating and alkalizing treatment on the accordion-shaped MXene material, thereby obtaining derived materials of different nanostructures. According to the method disclosed by the invention, through adopting the special layered MXene as a precursor, derived materials with a variety of unique nanostructures can be prepared in a regulated and controlled manner; and the method is easy and feasible, can be used for preparing nanostructures, which are not easily achieved by other methods, and has an important application prospect in the fields of electrochemical energy storage, catalysis, adsorption and the like.

The invention relates to a high-specific capacity lithium-sulfur battery positive electrode material and preparation method thereof. The lithium-sulfur battery positive electrode material is a sulfur-oxygen doped MXene-carbon nanotube composite material. The composite material is prepared according to the steps of taking MAX-phase ceramic powder as a raw material, preparing an MXene-carbon nanotube composite material by a vapor deposition method, obtaining an oxygen-doped MXene-carbon nanotube by hydrogen peroxide immersion, and performing sulfur doping by a ball-milling and hot melting method. When the sulfur-oxygen doped MXene-carbon nanotube composite material is used as a positive electrode material applied to the lithium-sulfur battery, the sulfur-oxygen doped MXene-carbon nanotube composite material has the characteristics of extremely high conductivity and large surface area, a discharging intermediate product lithium polysulfide can be effectively absorbed, and a shuttle effectis reduced.

The invention discloses a layered MXene loaded cobalt ferrite composite wave-absorbing material. The cobalt ferrite of the composite wave-absorbing material is loaded between layers of layered MXene, and the mass ratio of the cobalt ferrite to the layered MXene is 1: (1-3), wherein the MXene has a unique lamellar microstructure, and the surface of the MXene is rich in functional groups, so that the cobalt ferrite can be loaded between layers or on the surface of the MXene to form a dielectric-magnetic two-phase heterojunction microstructure, and the MXene has a remarkable dielectric polarization loss characteristic; the nano magnetic cobalt ferrite loaded on the MXene has a high-frequency natural resonance effect and a strong magnetic loss mechanism, and the high resistivity of the nano magnetic cobalt ferrite can weaken the strong reflection effect of the MXene on incident electromagnetic waves, so that the composite material is more beneficial to impedance matching with space; therefore, the composite material shows a broadband strong electromagnetic wave absorption characteristic, and a reflectivity result shows that the bandwidth of the composite material is superior to -10dB (90% absorption rate) and reaches 7.2 GHz, and a corresponding absorption peak reaches -21.75 dB.

The invention provides a ferrite material and MXenes composite material. Ferrite molecules are dispersed in a lamellar structure of MXenes. The ferrite material and MXenes composite material has good electrical conductivity, and accordingly, even when the temperature is lower than 260K, the ferrite material and MXenes composite material can still keep a certain electrical conductivity; the ferrite material and MXenes composite material good in impedance matching performance can be applied to various electronic parts and components such as anti-electromagnetic interference antennae, filters and inductance components by serving as a wave-absorbing material and is particularly applicable to wave absorption at low temperatures.

The invention relates to a Mxene@chitosan@polyurethane foam three-dimensional composite material and a high-sensitivity and high-reliability piezoresistive sensor constructed by using the material, and preparation methods thereof. The structure control of a conductive network and micro-cracks in the sensor and introduction of the structure system of Mxene@chitosan make a polyurethane skeleton firmly and closely coated with a conductive filler, so the stability of long-term recycling is greatly improved; and Mxene nanosheets have a small size, and the number of the micro-cracks produced by thepolyurethane-coated skeleton is high, and the detection under small strain is accurate. The Mxene@CS@PU composite three-dimensional structure with good stress strain can be obtained by optimizing theimpregnation frequency (1 to 5, and preferably 2) of a conductive filler in the preparation process of the sensor and the treatment steps of a technology of centrifugal removal of the Mxene nansheetsnot completely coating the skeleton and the drying temperature in the preparation process.

The invention relates to Mxene/PNIPAM/alginate composite thermal response hydrogel as well as preparation and application thereof. The hydrogel has a three-network structure, namely an MXene network,a poly(N-isopropylacrylamide) PNIPAM network and an alginate network, and physical crosslinking and chemical crosslinking are formed among the three networks. The preparation method comprises: preparing an MXene/NIPAM/alginate composite solution, carrying out in-situ polymerization, and sequentially putting the composite solution into a calcium chloride solution and deionized water for post-treatment. The preparation method is simple and feasible, and has an important value for preparing flexible actuators. The composite hydrogel has excellent thermal response performance and good mechanical properties, can respond to thermal stimuli by such as infrared light, and can perform telescopic actuation under a certain load.

The invention provides a method for preparing a laminated MXenes material from ternary MAX materials. Corrosion liquid is added into a pressure container; then, ternary MAX material powder is added into the corrosion liquid; the pressure container is sealed; through external gas pressure, a corrosion environment with the pressure higher than the atmospheric pressure is formed in the pressure container; corrosion is performed under the stirring condition at the corrosion liquid temperature of 4 to 60 DEG C; after the corrosion, the pressure is fast relieved; washing and drying are performed; the laminated MXenes materials are obtained. The method has the advantages that simplicity is realized; the operability is high; the realization result is good; the Mxenes material with good microtopography and high peeling degree can be obtained.

The invention discloses an MXene material and a preparation method and application thereof. A molecular formula of the MXene material is shown as M<n+1>X<n>Br<2> or M<n+1>X<n>I<2>, where M is Sc, Ti,V, Cr, Zr, Nb, Mo, Hf, Ta and the like, X is C and/or N element, and n is 1, 2, 3 or 4. The preparation method comprises the following steps: mixing a precursor MAX phase material, a transition metalbromide and/or a transition metal iodide, and carrying out a high temperature reaction to obtain the MXene material with Br or I as a surface group. The MXene material with Br or I as the surface group can be used independently as a large-capacity, high-stability halogen battery electrode, the -Br and -I groups can carry out a reversible redox reaction between MXene layers, a stable reaction source is provided for battery charging and discharging, and the feature is not possessed by other element groups such as -F, -Cl, and -O.

The invention relates to three-dimensional layered MXene electromagnetic shielding foam and a preparation method thereof and aims at solving the problems that an existing porous electromagnetic shielding material is low in absorbing and shielding effectiveness, poor in mechanical property and complicated in preparation process. According to the technical scheme, few-layer MXene dispersion liquid is prepared through wet chemical etching of an MAX phase; the dispersion liquid is directionally frozen through a bidirectional freezing process; and MXene aerogel is prepared through vacuum drying. The prepared MXene aerogel is of a layered structure, is long in range and ordered and has a good compression cycle characteristic, and the strength retention can reach over 60%. The total electromagnetic shielding effectiveness can reach 60-100dB; and the absorbing and shielding effectiveness can be adjusted through compressing the foam, so that the absorption-dominated electromagnetic shielding characteristic is achieved.

Provided is a MXene paper electrode and a preparation method thereof and a minitype supercapacitor and a preparation method, and mainly relates to the field of conducting materials. The preparation method of the MXene paper electrode prepares the MXene paper electrode by a spraying technology, so that the MXene paper electrode has the advantages that the MXene paper electrode is flimsy, flexible and low in cost; in addition, the minitype supercapacitor with paper support is prepared by overcoming the defect that most of traditional supercapacitor need current collectors, so that the minitype supercapacitor is flimsy and good in flexibility and the function of surface mounting technology of the minitype supercapacitor is easily achieved. Therefore, the MXene paper electrode and the preparation method thereof and the minitype supercapacitor and the preparation method have important promotion and application value and higher commercial value.

The invention provides a high voltage cable thermoplastic semiconducting shielding material and a preparation method thereof. The material is composed of the following components by weight: 15-40 parts of polypropylene, 30-50 parts of a polyolefin elastomer, 15-40 parts of conductive carbon black, 0.1-5.0 parts of an MXene-graphene (MXene-GNS) or MXene-carbon nanotube (MXene-CNT) or graphene-carbon nanotube (GNS-CNT) composite conductive powder, 0.5-10 parts of a lubricating dispersant, and 0.5-5.0 parts of an antioxidant. According to the invention, by adding the composite conductive filler,the dosage of conductive carbon black is reduced, and the processability of the shielding material is improved; the obtained semiconducting shielding material has high electrical conductivity, good conductivity temperature stability, good heat resistance and mechanical performance, and at the same time is non-crosslinked, green and environment-friendly.