Graphene oxide-modified electrode material for energy storage flow battery

Abstract

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.

Description

technical field [0001] The invention relates to the preparation and application of an electrode material for an energy storage liquid flow battery, in particular to an electrode for an all-vanadium flow battery and its application. Background technique [0002] Redox flow battery (VRB) is one of the most promising large-scale energy storage technologies. All-vanadium redox flow battery is a secondary battery with vanadium ion solution as positive and negative active materials, mainly composed of vanadium electrolyte , separator, electrode and current collector. The positive electrode electrolyte is V (V) and V (IV) sulfuric acid solution, and the negative electrode is V (III) and V (II) sulfuric acid solution. Through an external pump, the solution is pumped from the liquid storage tank into the battery stack, and the electrolyte flows through the graphite felt electrode for electrochemical reaction, and then the solution is transported back to the liquid storage tank. The...

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Problems solved by technology

Studies have shown that graphite felt electrodes loaded with iridium (Ir), indium (In) and other metals have good electrochemical catalytic activity, and pyrolytic reduction of H 2 IrCl 6 The preparation of Ir-modified carbon felt electrodes reduces the V(IV) / V(V) pair charge transfer resistance, but at the same time reduces the hydrogen evolution overpotential of the electrode, so it can only be applied to the modification of vanadium battery cathode materials

Bismuth (Bi) metal has a high hydrogen evolution overpotential. By thermal decomposition, electrodepositing nano-Bi metal on the surface of graphite felt can not only inhibit hydrogen evolution, but also promote the electrochemical redox of V(II) / V(III) reaction, but the metals Bi and Ir are noble metals, which are expensive, which limits their large-scale application

mn 3 o 4 , Nb 2 o 5 Such metal oxides can reduce the activation energy of the electrode reaction, increase the electrode reaction rate, reduce the chemical reaction kinetics, and have a good catalytic effect on the electrode reaction of the vanadium battery, but problems such as their low conductivity and unstable adhesion need to be solved urgently; (2 ) use heat treatment, acid treatment and electro-oxidation method to process graphite felt, increase the C-O, C=O and N functional groups on the surface of graphite felt, improve the electrochemical activity of the electrode, because the all-vanadium redox flow battery is carried out under a kind of flowing state During charging and discharging, these chemical functional groups will gradually fall off during the long-term reaction process, resulting in serious battery capacity attenuation

[0005] Although MinjoonPark etc. use CVD to grow carbon nanotubes and carbon nanofibers on the surface of carbon felt simultaneously (see reference: Synergistic effect of carbon nanofiber / nanotubecompositecatalystoncarbonfeltelectrodeforhigh-performanceall-vanadiumredoxflowbattery[J].Nanoletters,2013,13(10):4833-4839.) , which greatly improves the charge and discharge current density of the all-vanadium redox flow battery, showing high energy efficiency and voltage efficiency, but the preparation process of the electrode is complicated, the high temperature condition of the experiment causes a large amount of energy loss, and the follow-up treatment of the electrode is cumbersome. The electrode preparation process will consume a lot of manpower and material resources, so this electrode treatment process is not suitable for all-vanadium redox flow batteries

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