570 results about "Overpotential" patented technology

A system and method for calibrating a sensor of a characteristic monitoring system in real time utilizes a self-calibration module for periodic determination of, and compensation for, the IR drop across unwanted resistances in a cell. A current-interrupt switch is used to open the self-calibration module circuit and either measure the IR drop using a high-frequency (MHz) ADC module, or estimate it through linear regression of acquired samples of the voltage across the sensor's working and reference electrodes (Vmeasured) over time. The IR drop is then subtracted from the closed-circuit value of Vmeasured to calculate the overpotential that exists in the cell (Vimportant). Vimportant may be further optimized by subtracting the value of the open-circuit voltage (Voc) across the sensor's working and reference electrodes. The values of Vmeasured and Vimportant are then controlled by respective first and second control units to compensate for the IR drop.

Catalysts comprised of at least one catalytically active element and at least one helper catalyst are disclosed. The catalysts may be used to increase the rate, the selectivity or lower the overpotential of chemical reactions. These catalysts may be useful for a variety of chemical reactions including in particular the electrochemical conversion of carbon dioxide to formic acid.

A method of determining state of charge of an energy delivery device includes sampling voltage values of the energy delivery device during relaxation of the device. The method further includes regressing an open circuit voltage value and the total overpotential being relaxed. The regression includes a predetermined time constant of relaxation associated with the energy delivery device. One embodiment uses the equation V(t)=OCV−α exp(−t/tau), where V(t) represents the sampled voltage values, t represents times at which each of the voltage values are sampled, OCV represents the open circuit voltage value of the energy delivery device, α represents the overpotential value, and tau represents the time constant of relaxation. The method uses a predetermined profile that relates open circuit voltage of the energy delivery device to state of charge of the device, to determine a particular state of charge corresponding to the regressed open circuit voltage value.

The invention relates to an ultrathin nanosheet array electro-catalytic material with a nano-porous structure and oxygen vacancies. The material is a cobaltosic oxide primary nanosheet array which grows vertically on a conductive substrate and is doped with a metal; an ultrathin nanosheet with oxygen vacancies and nanopores is obtained on each primary nanosheet; the conductive substrate is a titanium sheet or a foamed nickel sheet, and the doped metal is zinc, nickel or manganese; and the thickness of each cobaltosic oxide ultrathin nanosheet doped with the metal is 1.22 nm, nanosheets are in a three-dimensional porous structure, and the nano-pore diameter is 3-6 nm. The ultrathin nanosheet array electro-catalytic material with the nano-porous structure and oxygen vacancies has the following advantages: the material can effectively reduce the overpotential and the spike potential of an oxygen evolution reaction, increase the conversion rate of a single cobalt atom and work continuously and stably in an alkali environment; the steps of a preparation method of the material are simple, the operation is convenient, the cost is low, and the material is environmental-friendly; and new ideas and strategies are provided for the function-oriented design and the performance optimization of an oxygen evolution catalyst of a water electrolysis system.

The invention discloses a zinc / polyhalide energy storage cell. An electrode of conductive inert material and an electrolyte solution of zinc chloride solution and zinc bromide solution are used to form a zinc / polyhalide energy storage cell. The zinc / polyhalide energy storage cell employs zinc and polyhalide with small electrochemical equivalent and high hydrogen evolution overpotential are used as active substances of the cell. Anode and cathode electric pair has high potential difference, and the two together decide that the cell technology has high energy density and power density. Compared with a zinc bromine liquid flow cell, a new system energy storage cell has energy density increased by 30%, power density increased by 10%, obviously enhanced removability and reduced cost of the cell system. The anode and the cathode of the cell employ electrolytes with a same element composition to avoid negative influence on cell performance and life caused by crossed contamination of electrolytes; the cell of the invention has advantages of long cycling life, low cost and good mobility and can be widely applied to fields of energy electric power, transportation and information communication, etc.

The invention relates to a graphene oxide-modified electrode material for an energy storage flow battery and a preparation method of the graphene oxide-modified electrode material. The electrode material comprises a carbon material matrix and a graphene oxide compound on the surface of the carbon material matrix. According to the method, graphene oxide is loaded on the surface of a carbon electrode by a hydrothermal process; the specific surface area of the modified electrode material is greatly increased; the contact area of an electrolyte and the electrode is increased; reactivity sites of the electrode and the electrolyte are increased; meanwhile, oxygen-containing functional groups of the modified electrode are rapidly increased; the internal resistance of electrochemical reaction of an all-vanadium redox flow battery electrode and the transport resistance of electrons are reduced; and overpotential of the battery under high current density is reduced, so that the voltage efficiency and the energy efficiency of an all-vanadium redox flow battery under the high current density are greatly improved.

The invention discloses a synthetic method for nitrogen-doped porous carbon N-C, and an application of the nitrogen-doped porous carbon in a positive electrode of a microbial fuel cell. The synthetic method comprises the following steps of taking melamine as a nitrogen source, and taking sodium citrate as a carbon source, mixing and grinding the melamine and the sodium citrate based on a certain proportion; and calcining the mixture in inert gas Ar at a temperature of 800 DEG C for 5h to successfully prepare the nitrogen-doped porous carbon N-C which is used as the microbial positive electrode material. The synthetic method and the application have the advantages as follows: on one hand, when the nitrogen-doped porous carbon N-C is used as the positive electrode of the microbial fuel cell, the attachment of electrogenesis microbes in the positive electrode can be facilitated; and on the other hand, the positive electrode activation overpotential is lowered, so that the electrogenesis power density of the microbial fuel cell is remarkably improved.

The invention relates to a nano-high-entropy alloy electrocatalyst and a preparation method thereof, and belongs to the technical field of new material preparation. The material is composed of a three-dimensional porous carbon substrate and FeCoNiCrCu high-entropy alloy nanoparticles loaded on the three-dimensional porous carbon substrate; the nanoparticles are an FeNi alloy structure monoclinic system, and the space group is Pm6; the molar ratio of Fe to Co to Ni to Cr to Cu is 1:1:1:1:1. The preparation method comprises the following steps: 1) dissolving a template agent-sodium chloride, a carbon source, and urea with deionized water, adding a doping source, magnetically stirring and freezing until totally solid, and then performing vacuum drying; 2) performing heat treatment and then cooling to room temperature to obtain powder; 3) washing, filtering and drying the powder to obtain the nano-high-entropy alloy electrocatalyst; 4) producing the nano-high-entropy alloy electrocatalyst into a working electrode and performing electrochemical performance test. The diameter of the nano-high-entropy alloy nanoparticles is 10 to 100 nm; according to a reaction of oxygen evolution through catalysis of the high-entropy alloy electrocatalyst, the initial potential is 1.50 to 1.63 V, the overpotential is 360 to 460 mV when the current density is 10 mA cm<-2>, and the Tafel slope is 70 to 120 mV dec<-1>.

The invention provides a preparation method of a carbon-coated transition metal phosphide composite material and application of the carbon-coated transition metal phosphide composite material to the oxygen evolution reaction. Firstly, a pointed transition metal hydroxide precursor containing anion intercalations of a phosphorus source and a carbon source between layers is prepared through synthesis, and then the podiform carbon-coated transition metal phosphide composite material is obtained through high-temperature roasting. The composite material is applied to the positive pole reaction-oxygen evolution reaction of electrolysis of water, can effectively improve the performance of a catalyst, namely lowering the take-off potential and improving catalytic activity, and is long in service life and good in stability. Meanwhile, raw materials of the composite material are low in cost and have abundant reserves, the preparation method is simple, and environment friendliness is achieved. Under the alkaline condition of 0.1-1 M KOH, the overpotential required by the electric current density of 10 mA/cm<2> is 280-340 mV, and the Tafel slope is 60-80 mV/dec; and under the constant voltage of 1.65 V, the circulation time is as long as 1-24 hours or longer.

The invention provides a three-dimensional multi-layered structure cobalt-nickel-aluminum ternary metal electrocatalyst for oxygen evolution reaction as well as a preparation and application method thereof. The electrocatalyst is based on layered double hydroxides (LDHs) and zeolite imidazole metal-organic frameworks (ZIF-67), nickel foam (NF) serves as a substrate, and a ZIF-67/CoNiAl-LDH/NF three-dimensional multi-layed structure catalyst is synthesized through a two-step hydrothermal method. The electrocatalyst as well as the preparation and application method thereof have the advantages that through the introduction of the two-dimensional ZIF-67, the electrochemical active area of the catalyst can be improved, the formed unique three-dimensional multi-layed porous structure and a carrier with high specific surface area and abundant pore channels are beneficial for reducing the potential barrier of the oxygen evolution reaction, in addition, a super-hydrophobic interface is formed between a solid phase and a liquid phase, so that oxygen can be easily desorbed, the occurrence of the oxygen evolution reaction can be promoted, the electrocatalyst is applied to the oxygen evolutionreaction, the electric current density is 10 mA/cm<2>, the reaction overpotential is 0.3-0.41V, the Tafel slope is 88-245 mV/dec<-1>, in addition, the stability is good, and a good application prospect can be achieved.

The invention relates to electrochemical power sources and the field of electrochemical catalysis, and particularly relates to a transition metal nitride/carbon electrocatalyst. The transition metal nitride/carbon electrocatalyst comprises a substrate and a shell, the substrate is coated by the shell, and the shell comprises copper nitride and further comprises a carbon material or a nitrogen doped carbon material. The invention further provides a preparation method of the electrocatalyst, and the electrocatalyst is prepared by forming MOF of copper in advance, then further aminating and calcining through one step, and preparing the electrocatalyst. The processes of oxygen precipitation and hydrogen precipitation show the low overpotential in the alkaline environment, and the electrocatalyst can be used as a catalyst material of alkaline efficient electrolysed water.

The invention discloses a metal organic skeleton compound-based cobalt-carbon porous nanocomposite oxygen reduction electrocatalyst and its preparation method and application. The cobalt-carbon porous nanocomposite oxygen reduction electrocatalyst is prepared from a metal organic skeleton compound [Co(O-BDC)(bbp)] as a precursor through high-temperature calcination. The carbon material has a porous structure. A cobalt element is uniformly supported on the carbon material. The oxygen reduction electrocatalyst has high electrical conductivity and a large specific surface area and effectively reduces the overpotential of oxygen reduction. Through a rotating disk electrode and a rotating ring electrode, it is proved that the oxygen reduction process is an ideal 4 electron oxygen reduction catalytic process. The electrocatalyst fully performs synergism of cobalt and a carbon material in electrocatalysis and has great theoretical and practical significance for the development of novel electrochemical catalysts and energy conversion and storage devices.

The invention discloses a preparation method of N-doped porous carbon coated nano-particles (Co@Ir/NC-x, and x is the quality ratio of Ir) of a Co-Ir core-shell structure and application of the N-doped porous carbon coated nano-particles of the Co-Ir core-shell structure to catalytic water splitting. The preparation method has the advantages that (1) the preparation process is simple and direct, and energy consumption is low, specifically, Co/NC obtained after a zeolite imidazole framework material (ZIF-67 for short) is calcined is directly subjected to Galvanic replacement with Ir<3+> at theroom temperature, high temperature and high pressure are not needed, and accordingly the energy consumption is low; (2) the catalytic performance is good, and the stability is high, specifically, a Co@Ir/NC-10% sample is in a 1M KOH solution, in an oxygen producing test, the current density is 10 mA cm<-2>, the overpotential is 280 mV, and the performance is higher than IrO2; in a hydrogen producing test, the current density is 10 mA cm<-2>, the overpotential is -121 mV; besides, after a stability test of 12 h, the oxygen producing activity of IrO2 is attenuated by 55.8% while the oxygen producing activity of Co@Ir/NC-10% is attenuated only by 20.6%, and the hydrogen producing stability of Co@Ir/NC-10% is far higher than that of commercial Pt/C under the same conditions; and (3) the catalyst cost is low and the Co source is wide, specifically, the nano-particles are of the core-shell structure with Co as a core and Ir as a shell, the amount of Ir is reduced on the basis of more exposedcatalytic activity sites, a core metal precursor Co is wide in source and low in cost, the catalyst cost is greatly reduced, and great commercial application prospects are achieved.

The invention belongs to the field of a lithium battery electrode material and particularly discloses a 3D lithium-philic porous metal current collector. The current collector comprises a 3D porous metal current collector and at least one of gold, silver and platinum compounded on a framework of the 3D porous metal current collector. The invention further discloses a preparation method and an application of the metal current collector. A 3D lithium-philic porous lithium ion negative electrode is particularly prepared. The current collector is advantaged in that at least one metal of gold, silver and platinum on the porous metal framework reduces the overpotential in the lithium metal nucleation and deposition process, uniform deposition and dissolution of lithium metal in the continuous cycle process are realized, growth of dendrites is effectively avoided, and the cycle life of a lithium metal battery is greatly prolonged.

The invention provides a porous-carbon loaded metal composite material and a preparing method and application thereof. The method includes the steps that NiMoO4 nanometer rods and carbon-source monomers are reacted in Tris reagent solutions to obtain NiMoO4/carbon source precursors; the NioMO4/carbon source precursors are calcined to obtain the porous-carbon loaded metal composite material. The porous-carbon loaded metal composite material comprises porous-carbon carriers, nickel and molybdenum carbide, wherein the nickel and the molybdenum carbide are loaded to the porous-carbon carriers. The method is simple in step and easy to operate, and has the advantages of being convenient, rapid and the like. The porous-carbon loaded nickel and molybdenum carbide composite material has the excellent catalyzing electrochemistry hydrogen-producing and oxygen-producing performance and the excellent full water decomposition performance. An experiment shows that when the composite material serves as a catalyst in a hydrogen producing reaction, and when the overpotential is 0.25 V, the electric current density can be 52 mA/cm<2>; in a full hydrolysis reaction, when the electric potential is 1.68 V, the electric current density can be 10 mA/cm<2>, the performance is excellent, and the porous-carbon loaded metal composite material has the good application prospect in the field of electro-catalysis hydrogen producing and oxygen producing and the field of full water decomposition.

The invention discloses a flexible three-dimensional porous nitrogen-doped carbon nanotube/cobalt phosphide composite material and a preparation method and application thereof. According to the flexible three-dimensional porous nitrogen-doped carbon nanotube/cobalt phosphide composite material and the preparation method and application thereof, low-cost commercial melamine sponges are used as a three-dimensional carbon material skeleton template, a zeolite imidazole structure metal organic framework is used as a cobalt source, phosphorization is carried out by a low-temperature vapor deposition method, and the flexible three-dimensional porous nitrogen-doped carbon nanotube/cobalt phosphide composite material with high conductivity and a high specific surface area is obtained. The preparation process of the flexible three-dimensional porous nitrogen-doped carbon nanotube/cobalt phosphide composite material is relatively simple, the cost is low, and the preparation process is suitable for industrial application. The flexible three-dimensional porous nitrogen-doped carbon nanotube/cobalt phosphide composite material is used as an electrode material for hydrogen evolution catalysis ofelectrolyzed water, and has lower hydrogen evolution catalysis overpotential, a larger electrocatalytic active area and excellent cycle stability.

The invention discloses a lithium metal composite negative electrode with a lithium-philic and lithium-phobic gradient structure, and a preparation method thereof. The lithium metal composite negativeelectrode is of a three-layer structure, wherein the bottom layer is a 3D porous matrix framework, the middle layer is a lithium-philic layer compounded on the 3D porous matrix framework, and the toplayer is a lithium-phobic layer compounded on the surface of the lithium-philic layer. The preparation method comprises the following steps: (1) preparing a 3D porous matrix skeleton, and cleaning; (2) transferring the 3D porous matrix skeleton to a prepared precursor solution; (3) forming a lithium-philic layer on the 3D porous matrix skeleton in situ by adopting a solvothermal method; (4) modifying a lithium-phobic layer on the lithium-philic layer; and (5) finally filling with lithium by adopting an electro-deposition method. According to the invention, the overpotential in the lithium metal nucleation and deposition process can be reduced by utilizing the lithium-philic layer, and the uniform deposition and dissolution of the lithium metal in the continuous cycle process are realizedby utilizing the characteristic that the lithium ion diffusion is promoted by utilizing the lithium-phobic layer, so that the growth of dendritic crystals is effectively avoided, and the cycle life ofthe lithium metal battery is greatly prolonged.