A vanadium/chloride electrolyte and a redox flow battery using the electrolyte

Abstract

The present invention belongs to the technical field of flow energy storage batteries, and relates to a vanadium / chloride electrolyte and a redox flow battery using the vanadium / chloride electrolyte. According to the present invention, an electric conduction inert material is adopted as the electrode, the electrolyte adopts hydrochloric acid as the supporting electrolyte, and Cl<-> ions are introduced, such that the existing form of V is the stable dual-core vanadium ions [V2O3.4H2O]<4+> or dual-core vanadium-chlorine composite ion [V2O3Cl.3H2O]<3+> and is more stable than the V existing form [VO2(H2O)3]<+> in the electrolyte adopting sulfuric acid as the supporting electrolyte, and the stability of the vanadium cations is increased while the concentration of the vanadium cations in the electrolyte is improved so as to increase the energy density of the battery system; when the battery system electrolyte temperature is greater than 40 DEG C, the two existing forms of V are stable and no V2O5 precipitate can be generated; and the battery system work temperature range is wide, and the battery system can stably work within a temperature range of 0-65 DEG C so as to eliminate the electrolyte temperature control device, reduce the battery system cost, and improve the system efficiency.

Description

technical field [0001] The invention belongs to the technical field of liquid flow energy storage batteries, in particular to a vanadium / chloride electrolyte and a redox flow battery using the electrolyte. Background technique [0002] In the current world, the problem of energy shortage and environmental pollution caused by fossil energy is becoming increasingly acute. Under the dual pressure of energy security and environmental protection, new energy technologies such as wind energy and solar energy have been widely valued due to their renewable characteristics. However, wind power and solar power generation are intermittent, which has become a major bottleneck restricting their development. The all-vanadium redox flow battery has the remarkable characteristics of deep charge and discharge, long life, easy operation, easy maintenance, and environmental protection. It can be used for smooth output of renewable energy such as wind energy and solar energy, and realizes peak-...

AI Technical Summary

Problems solved by technology

At present, the electrolyte of all-vanadium redox flow batteries reported in domestic and foreign literature usually uses sulfuric acid as a supporting electrolyte, and the specific energy of the battery system is 25-35Wh / Kg, which is relatively low and cannot meet the needs of development and customer needs.

[0004] At present, the way to improve the performance of the electrolyte is mainly by increasing the content of vanadium per unit volume. This method is relatively simple and easy to operate, but this method has obvious disadvantages.

When the concentration of vanadium ions is higher than 1.8mol / L, the positive electrode electrolyte after charging is easy to hydrolyze out V when the temperature is higher than 40°C. 2 o 5 Precipitation (2VO 2 +H 2 O=V 2 o 5 +2H + ); after discharge, the negative electrode electrolyte is easily saturated and precipitated when the temperature is lower than 10°C 2 (SO 4 ) 3 Crystallization will greatly reduce the capacity of the electrolyte, and more seriously, the formed precipitate will block the internal transmission pipeline of the battery, resulting in irreversible attenuation of the entire battery performance

Although the electrolyte temperature control device can be used to ensure the normal operation of the battery system, the temperature control device increases the complexity of the system, which limits the popularization and application of all-vanadium redox flow batteries.

On the other hand, the method to improve the stability of the anolyte of the all-vanadium redox flow battery is mainly to add additives, but so far there is no additive formula that can effectively improve the high temperature stability of the positive electrode electrolyte and the low temperature stability of the negative electrode electrolyte at the same time.

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