CN-122000398-A - Composite graphite felt electrode and preparation method and application thereof

Abstract

The invention discloses a composite graphite felt electrode, a preparation method and application thereof, and belongs to the technical field of electrode materials of all-vanadium redox flow batteries. The constructed laminated coating forms a heterojunction at the interface of the amorphous titanium nitride and the transition metal nitride by constructing a heterogeneous interface, thereby effectively regulating and controlling the interface electronic structure, remarkably promoting the charge separation and transmission efficiency in the electrode reaction process, and greatly improving the oxidation-reduction reaction kinetics of vanadium ions. Meanwhile, the inherent excellent conductivity and chemical stability of the titanium nitride and the synergistic effect of the titanium nitride and the transition metal nitride enable the electrode to show excellent corrosion resistance and structural stability in the strong acid and strong oxidizing environment of the all-vanadium redox flow battery, and the electrode is endowed with lower polarization, higher energy efficiency and longer cycle life.

Inventors

• SONG ZHONGXIAO
• NIE YAHONG
• YANG YANG
• QIAN DAN
• XIONG SHIZHAO
• QIU GUIZHI
• WU JIAN

Assignees

• 西安交通大学
• 中国大唐集团科学技术研究总院有限公司
• 中国大唐集团科学技术研究总院有限公司华北电力试验研究院

Dates

Publication Date

20260508

Application Date

20260130

Claims (10)

1. 1. The composite graphite felt electrode is characterized in that amorphous titanium nitride layers and transition metal nitride layers are alternately deposited on the surface of a graphite felt substrate, and heterojunction is formed at the interface of the amorphous titanium nitride layers and the transition metal nitride layers to form a laminated coating of amorphous titanium nitride and transition metal nitride; The thickness of the laminated coating is 5 nm-100 nm; the transition metal nitride is at least one selected from the group consisting of vanadium nitride, zirconium nitride, niobium nitride, tantalum nitride, hafnium nitride, and molybdenum nitride.
2. 2. A method of making a composite graphite felt electrode according to claim 1, comprising the steps of: Absorbing a titanium source precursor on the surface of a graphite felt by atomic layer deposition by taking the graphite felt as a substrate and taking the titanium source precursor as a raw material at 80-150 ℃, and then carrying out pulse nitridation by using first nitrogen-hydrogen mixed gas plasma, and alternately circulating the atomic layer deposition and the pulse nitridation of the first nitrogen-hydrogen mixed gas plasma to form an amorphous titanium nitride layer; And depositing a transition metal source precursor on the surface of the amorphous titanium nitride layer by atomic layer deposition by taking the transition metal source precursor as a raw material, and then carrying out pulse nitridation by using plasma of a second nitrogen-hydrogen mixed gas, and alternately circulating the atomic layer deposition and the pulse nitridation of the second nitrogen-hydrogen mixed gas plasma to form a transition metal nitride layer to obtain the composite graphite felt electrode.
3. 3. The method for preparing the composite graphite felt electrode according to claim 2, wherein the steam pulse flow rates of the titanium source precursor and the transition metal source precursor are 50 sccm-200 sccm, and the flow rates of the first nitrogen-hydrogen mixed gas and the second nitrogen-hydrogen mixed gas are 20 sccm-100 sccm.
4. 4. The method for preparing the composite graphite felt electrode according to claim 3, wherein the volume ratio of nitrogen to hydrogen in the first nitrogen-hydrogen mixed gas to the second nitrogen-hydrogen mixed gas is 1-4:1.
5. 5. The method for preparing the composite graphite felt electrode according to claim 2, wherein in the preparation process of the amorphous titanium nitride layer, the alternating cycle number of atomic layer deposition and pulse nitridation of the first nitrogen-hydrogen mixed gas plasma is 10-500 times; In the preparation process of the transition metal nitride layer, the alternating cycle times of atomic layer deposition and pulse nitridation of the second nitrogen-hydrogen mixed gas plasma are 1-100 times.
6. 6. The method for manufacturing a composite graphite felt electrode according to claim 2, wherein the manufacturing process of the amorphous titanium nitride layer and the transition metal nitride layer is alternately repeated 1 to 500 times.
7. 7. The method for preparing the composite graphite felt electrode according to claim 2, wherein the titanium source precursor is titanium tetrachloride, tetra (dimethylamino) titanium or isopropyl titanate, and the transition metal source precursor is at least one selected from vanadium pentachloride, vanadyl acetylacetonate, zirconium tetra (diethylamino), niobium pentachloride, t-butylimide tris (ethylmethylamino) tantalum, hafnium tetra (dimethylamino) and molybdenum pentachloride.
8. 8. The preparation method of the composite graphite felt electrode according to claim 2 is characterized in that argon purging is conducted for 10 s-60 s after a titanium source precursor is adsorbed on the surface of a graphite felt through atomic layer deposition, argon purging is conducted for 5 s-30 s after pulse nitridation of first nitrogen-hydrogen mixed gas plasma, argon purging is conducted for 10 s-60 s after a transition metal source precursor is deposited on the surface of an amorphous titanium nitride layer through atomic layer deposition, and argon purging is conducted for 5 s-30 s after pulse nitridation of second nitrogen-hydrogen mixed gas plasma.
9. 9. The method for preparing the composite graphite felt electrode according to claim 8, wherein argon with the flow rate of 100-300 sccm is adopted for purging.
10. 10. Use of the composite graphite felt electrode of claim 1 as a negative electrode of an all-vanadium flow battery.

Description

Composite graphite felt electrode and preparation method and application thereof Technical Field The invention relates to the technical field of electrode materials of all-vanadium redox flow batteries, in particular to a composite graphite felt electrode and a preparation method and application thereof. Background With the rapid increase of the duty ratio of intermittent renewable energy sources such as wind power, photovoltaic and the like in a global energy structure, the development of a large-scale, long-term, safe and reliable energy storage technology has become a key for supporting a novel power system. All-vanadium redox flow batteries are considered as one of the most promising large-scale energy storage technologies by virtue of the outstanding advantages of decoupling power and capacity, extremely long cycle life, high safety, recyclable electrolyte and the like. The electrode is used as a core component of the all-vanadium redox flow battery, and the performance directly influences the energy efficiency and the cycling stability of the battery. Graphite felt is widely used as electrode material of all-vanadium redox flow battery, but the inherent hydrophobicity and the insufficient surface active sites limit the catalytic activity of the graphite felt on vanadium redox reaction. Aiming at the problems, the prior modification strategy mainly introduces oxygen-containing functional groups or heteroatoms (N, B, P and the like) on the surface of the graphite felt by surface modification technologies such as heat treatment, plasma treatment and the like so as to improve the hydrophilicity and the density of active sites. However, such surface modification is generally limited to shallow layers, excessive etching can impair the mechanical properties of the fibers, and in strong acid and highly oxidizing environments, oxygen-containing functional groups are easily reduced or hydrolyzed, resulting in rapid decay of electrode activity. In addition, there have been researchers anchoring noble metals, non-noble metal oxides or carbon-based nanomaterials to the electrode surface by dip-pyrolysis, in situ polymerization or electrodeposition to enhance electrocatalytic performance. Although the method can obviously promote charge transfer, the method has the problems of complex process, higher cost, easy agglomeration and falling of the catalyst and pollution of electrolyte caused by noble metal dissolution, and causes capacity attenuation and cycle life reduction of the battery. In recent years, transition metal nitrides have shown great potential in the modification of all-vanadium redox flow battery electrodes due to their unique electronic structure and noble metal-like catalytic properties. Among them, titanium nitride has received attention because of its high conductivity, excellent mechanical strength, and good corrosion resistance. However, the nitride modified graphite felt electrode prepared by the existing method still faces the problems of insufficient exposure of active sites and low electron conduction efficiency due to the fact that a coating with uniform, compact and accurate components and controllable thickness is difficult to construct on a complex three-dimensional substrate, and the problems of insufficient exposure of active sites and low electron conduction efficiency are still faced, which severely limit the stability and the electrocatalytic efficiency of the nitride modified graphite felt electrode under high current density. Disclosure of Invention The invention provides a composite graphite felt electrode, a preparation method and application thereof, which effectively solve the technical problems of insufficient exposure of active sites and low electronic conduction efficiency of electrode materials still caused by modifying the graphite felt electrode by adopting nitrides, the invention forms uniform and compact titanium nitride-based composite coating with accurate components and controllable thickness on the fiber surface of the three-dimensional porous structure of the graphite felt by utilizing the atomic layer deposition technology, thereby effectively improving the lyophilic property, electrochemical activity and long-term stability of the graphite felt. The first object of the present invention is to provide a composite graphite felt electrode, wherein amorphous titanium nitride layers and transition metal nitride layers are alternately deposited on the surface of a graphite felt substrate, and a heterojunction is formed at the interface of the amorphous titanium nitride layers and the transition metal nitride layers, so that a laminated coating of amorphous titanium nitride and transition metal nitride is formed. The thickness of the laminated coating is 5 nm-100 nm. The transition metal nitride is at least one selected from the group consisting of vanadium nitride, zirconium nitride, niobium nitride, tantalum nitride, hafnium nitride, and molybdenum nitride. The second