Preparation method of multi-transition metal nitride zinc air battery cathode material
阅读说明：本技术 一种多过渡金属氮化物锌空气电池阴极材料的制备方法 (Preparation method of multi-transition metal nitride zinc air battery cathode material ) 是由 徐丽 邓代洁 李赫楠 于 2019-10-22 设计创作，主要内容包括：本发明属于锌空气电池领域，具体涉及一种多过渡金属氮化物锌空气电池阴极材料的制备方法及其在锌空气电池领域的应用。具体制备方法包括以下步骤：通过在水中溶解碳酸胍和过渡金属盐得到过渡金属盐溶液；将得到的过渡金属盐溶液进行冷冻干燥处理，得到海绵状固体；最后将上述海绵状固体在惰性气体保护下高温煅烧得到多过渡金属氮化物多孔网状材料。多过渡金属氮化物多孔网状材料可作为氧还原电催化剂，并表现出优异的稳定性。作为锌空气电池空气阴极催化剂材料，该催化剂材料表现出了较强的充放电长期循环性，具有非常可观的实际应用前景。此外，此合成方法操作简单，普适性强。(The invention belongs to the field of zinc-air batteries, and particularly relates to a preparation method of a multi-transition metal nitride zinc-air battery cathode material and application of the multi-transition metal nitride zinc-air battery cathode material in the field of zinc-air batteries. The preparation method comprises the following steps: obtaining a transition metal salt solution by dissolving guanidine carbonate and a transition metal salt in water; freeze-drying the obtained transition metal salt solution to obtain a spongy solid; and finally, calcining the spongy solid at high temperature under the protection of inert gas to obtain the multi-transition metal nitride porous mesh material. The multi-transition metal nitride porous mesh material can be used as an oxygen reduction electrocatalyst and shows excellent stability. As the air cathode catalyst material of the zinc-air battery, the catalyst material shows stronger charge-discharge long-term cyclicity and has very considerable practical application prospect. In addition, the synthesis method is simple to operate and strong in universality.)
1. A preparation method of a multi-transition metal nitride zinc-air battery cathode material is characterized by comprising the following steps:
(1) dissolving a transition metal salt in a guanidine carbonate aqueous solution, and stirring at room temperature to form a transition metal salt solution;
(2) dispersing locust bean gum in the transition metal salt solution in the step (1) to form viscous liquid;
(3) freezing and drying the viscous liquid obtained in the step (2) to obtain a spongy solid;
(4) putting the spongy solid obtained in the step (3) into a porcelain crucible with a cover and then putting the porcelain crucible into a tubular furnace; keeping the temperature at 800-1000 ℃ for 1-2h under the inert gas atmosphere; naturally cooling to room temperature to obtain black powder.
2. The method according to claim 1, wherein in the step (1), the concentration of the guanidine carbonate aqueous solution used is 0.015 g/mL.
3. The method according to claim 1, wherein in the step (1), one of the transition metal salts used is Zn (NO)3)2·6H2O; the second is one of iron salt, cobalt salt, copper salt, manganese salt, nickel salt, molybdenum salt or chromium salt.
4. The method according to claim 1, wherein the temperature of the freeze-drying in the step (3) is-10 to-100 ℃.
5. The method according to claim 1, wherein in the step (4), the inert gas is high-purity argon gas.
6. The method according to claim 1, wherein in steps (1) to (4), the mass ratio of the locust bean gum, the transition metal salt and the guanidine carbonate is: 1: 2-4: 1-5.
7. A multi-transition metal nitride zinc-air battery cathode material is characterized by being prepared by the preparation method of any one of claims 1-6.
8. Use of the multi-transition metal nitride zinc-air cell cathode material of claim 7 as a zinc-air cell cathode material.
Technical Field
The invention belongs to the field of air batteries and fuel batteries, and particularly relates to a preparation method of a multi-transition metal nitride zinc-air battery cathode material and application of the multi-transition metal nitride zinc-air battery cathode material in the field of zinc-air batteries.
Background
Nowadays, energy and environmental protection are two important subjects of the present society, and in order to meet the ever-increasing huge demand of human beings, a novel energy storage and conversion device is very important. As a common energy storage and conversion device, the metal-air battery has the characteristics of low cost, environmental protection, no pollution, safety and high theoretical energy density. During operation of a metal air battery, the Oxygen Reduction Reaction (ORR) involved in the air cathode is an important basic reaction that determines the operating efficiency of the battery. However, the oxygen reduction reaction still has the disadvantage of severe slow kinetics. In order to accelerate the kinetics of the oxygen reduction reaction, the use of a catalyst in the reaction process is one of the better solutions. Currently, platinum-based catalysts show the best catalytic performance in catalyzing oxygen reduction reactions. The small inventory of platinum-based catalysts and their instability and susceptibility to poisoning limit their commercial use on a large scale, and also greatly limit the operating efficiency of the cells when assembling metal-air cells. Therefore, the preparation of non-noble metal catalysts with low price and excellent stability becomes a research hotspot in recent years.
In order to replace platinum-based catalysts, a series of transition metal-based materials, which are abundant in earth and inexpensive, have been extensively studied and used by research teams on a global scale for catalyzing oxygen reduction reactions. Among them, transition metal nitrides exhibit unique electronic structures, excellent electrochemical conductivity, and better resistance in aqueous solutions. The nitrogen atoms in the metal nitride can cause the d band of the metal element to shrink, and the electron density near the Fermi level of the metal nitride is improved, so that the transport of electrons between the metal nitride and an adsorbate is facilitated, and the oxygen reduction reaction is further promoted. Furthermore, the introduction of multi-metallic active sites is also beneficial for breaking the O-O bonds in the oxygen molecule compared to single metallic active sites. In order to improve the utilization efficiency of the multi-metal sites, it is considered to disperse the multi-metal sites as much as possible to improve the density of the active sites available during the reaction. In general, porous carbon materials are often used as a framework for preparing oxygen reduction catalysts, dispersing as much as possible the multi-metallic active sites in the catalyst. However, how to obtain the porous carbon material loaded with multiple metal active sites through simple experimental operation is still a great problem in the preparation process of the oxygen reduction catalyst. Most of the catalyst preparation methods used by the current research team have complicated synthesis steps and do not have universality. Therefore, in the process of preparing the oxygen reduction catalyst, researchers need to consider whether the preparation cost of the catalyst is low, whether the experimental steps are simple and easy to operate, and whether the preparation method has universality, and also need to consider whether the preparation method can prepare the catalyst on a large scale.
Disclosure of Invention
Aiming at the defects existing in the preparation process of the cathode catalyst material of the existing air battery, the invention aims to disclose a preparation method of a zinc nitride air electrode cathode material with multiple transition metals. The method has the advantages of high universality, simple and convenient operation and low cost. The prepared multi-transition metal nitride has high-activity electrochemical properties and excellent long-term cycling stability. Especially, the catalyst shows longer charge-discharge cycle performance in the application of zinc-air batteries, and far exceeds the commercial platinum-carbon catalyst.
A preparation method of a multi-transition metal nitride zinc-air battery cathode material comprises the following steps:
(1) dissolving a transition metal salt in a guanidine carbonate aqueous solution, and stirring at room temperature to form a transition metal salt solution;
(2) dispersing locust bean gum in the transition metal salt solution in the step (1) to form viscous liquid;
(3) freezing and drying the viscous liquid obtained in the step (2) to obtain a spongy solid;
(4) putting the spongy solid obtained in the step (3) into a porcelain crucible with a cover and then putting the porcelain crucible into a tubular furnace; keeping the temperature at 800-1000 ℃ for 1-2h under the inert gas atmosphere; naturally cooling to room temperature to obtain black powder.
In the step (1), the concentration of the guanidine carbonate aqueous solution used was 0.015 g/mL.
In the step (1), one of the transition metal salts is Zn (NO)3)2·6H2O; the second is one of iron salt, cobalt salt, copper salt, manganese salt, nickel salt, molybdenum salt or chromium salt.
In the step (3), the temperature of the freeze drying is-10 to-100 ℃.
In the step (4), the inert gas is high-purity argon.
In the steps (1) - (4), the mass ratio of the locust bean gum, the transition metal salt and the guanidine carbonate is as follows: 1: 2-4: 1-5.
The multi-transition metal nitride zinc-air battery cathode material prepared by the invention is used for zinc-air battery cathode materials.
The multi-transition metal nitride zinc-air battery cathode material prepared by the invention has excellent ORR catalytic activity.
The concrete expression is as follows:
when the multi-transition metal nitride zinc-air battery cathode material catalyzes ORR reaction, the half-wave potential reaches 0.84V, and the limiting current density (6.10mA cm)-2) Better than the commercial 20 wt% Pt/C catalyst (6.15mA cm)-2)。
The multi-transition metal nitride zinc-air battery cathode material provided by the invention has the advantage of strong charge-discharge long-term cycle stability in practical application, and the cycle period is as long as 115 h.
The high-efficiency electrocatalytic activity of the cathode material of the multi-transition metal nitride zinc-air battery prepared by the invention is benefited by the following steps:
(1)MNxthe inherent polarity, excellent electrochemical conductivity and strong tolerance of (M ═ Fe, Co, Cu, Ni, Cr, Mn, Mo) species ensure the oxygen reduction reactivity of the catalyst;
(2) the introduction of the second metal can not only change the MNxThe electronic structure of (2) can also form a multi-metal active site, which is beneficial to the adsorption of oxygen;
(3) in the reaction process, the multi-metal active sites are more beneficial to promoting the adsorption of reaction intermediates, so that more excellent catalytic activity is caused;
(4) the pore network carbon structure expressed by the catalyst can disperse the multi-metal active sites as much as possible, and the utilization efficiency of the multi-metal active sites is improved; but also can improve the conductivity of the catalyst;
(5) the abundant porous structure and defect structure shown in the catalyst can also promote mass transfer effect during the reaction process.
The invention has the beneficial effects that:
(1) selecting guanidine carbonate to obtain an alkaline solution, and preparing a porous reticular carbon material through a subsequent high-temperature calcination process by utilizing the principle that a galactose structure in locust bean gum can be subjected to polycondensation reaction under a weak alkaline condition to form a polycarbon compound;
(2) the multi-transition metal nitride zinc-air battery cathode material has abundant pore structures;
(3) the combination of the porous reticular carbon material and the multi-metal active sites greatly prevents the aggregation of metal species and ensures the formation of small-sized metal particle species;
drawings
FIG. 1 is (a) a Scanning Electron Microscope (SEM), (b) a Transmission Electron Microscope (TEM) image, (c, d) a high resolution electron microscope (HR-TEM) image of the Zn/CoN-NC catalyst in example 1;
FIG. 2 is (a) an X-ray diffraction (XRD) pattern and (b) a Raman spectrum (Raman) pattern of the Zn/CoN-NC catalyst in example 1;
FIG. 3 shows (a) a high resolution X-photoelectron spectrum (XPS) of C element, (b) a high resolution X-photoelectron spectrum (XPS) of N element, (C) a high resolution X-photoelectron spectrum (XPS) of Co element, (d) a high resolution X-photoelectron spectrum (XPS) of Zn element of the Zn/CoN-NC catalyst of example 1;
in FIG. 4, (a) is the Zn/CoN-NC of example 1 and a commercial grade of 20 wt% Pt/C catalyst in O2Saturated 0.1 mol. L-1Linear Sweep Voltammetry (LSV) curve at catalytic ORR in KOH electrolyte, with electrode rotation speed of 1600 rpm; (b) is a Zn/CoN-NC and
FIG. 5 shows an embodimentIn example 1, the Zn/CoN-NC catalyst was used as a negative electrode material for a zinc-air battery at 10mA cm-2And (3) a test curve of the long-term charge-discharge cycle stability measured under the current density.
Detailed Description
The patent relates to a preparation method of a multi-transition metal nitride zinc-air battery cathode material and application of the multi-transition metal nitride zinc-air battery cathode material in zinc-air battery cathode catalysts. The experimental details of the present invention will be described in full and clearly with reference to the following experimental technical solutions and specific examples so that those skilled in the art can better understand the present invention.
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