A neutral zinc-iodine flow battery

Abstract

The invention relates to a zinc-iodine single-flow battery. The zinc-iodine single-flow battery includes a single cell or a stack composed of two or more single-cell circuits connected in series. The single cell includes sequentially stacked positive end plates, current collectors, belt Positive electrode with liquid flow frame, membrane, negative electrode with liquid flow frame, negative end plate, the electrolyte in the negative electrode electrolyte storage tank realizes the circulation of electrolyte between the negative electrode cavity and the storage tank through the pump, and at the same time, the negative electrode pipeline A branch pipeline for positive electrolyte circulation is provided. The porous membrane between the positive and negative electrodes of the battery realizes conduction to support the electrolyte and prevents I 3 ‑ Diffusion to the negative electrode. The electrolyte active material has high solubility and high energy density, which is especially suitable for the construction of single-flow batteries; at the same time, the positive and negative electrolyte solutions are neutral, which overcomes the corrosion problem of strong acid and strong alkali electrolytes in traditional flow batteries. At the same time, the battery High current density, long cycle life and low cost.

Description

technical field [0001] The invention relates to the field of flow batteries, in particular to the field of zinc-iodine flow batteries. Background technique [0002] Extensive use of fossil energy has caused energy crisis and environmental problems. The development and utilization of non-renewable energy has become the focus of attention of countries all over the world. However, the discontinuity and instability of renewable energy such as wind energy and solar energy make their direct utilization difficult. Therefore, using energy storage technology to achieve continuous supply of renewable energy becomes the key to solving the above problems. Flow batteries have become one of the most promising technologies in the large-scale energy storage market due to their flexible design (separate design of energy and power), good safety, and long design life. Among them, all-vanadium flow batteries have already Enter the commercial demonstration stage. [0003] At present, the rela...

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Problems solved by technology

However, because the battery needs electrolyte circulation systems such as pumps and storage tanks, the energy efficiency of the system is greatly reduced due to system losses. On the other hand, battery auxiliary equipment such as pumps and storage tanks make the structure of the battery system complex and reduce the energy density of the system. Therefore, it is an important method to improve the energy utilization efficiency and energy density of the system to carry out the research on the single flow battery on the basis of the double flow and reduce the energy loss of the system.

In addition, currently reported zinc-iodine flow batteries mostly use expensive perfluorosulfonic acid ion-exchange membranes, but the above-mentioned ion-exchange membranes are easily contaminated in the zinc-iodide system, resulting in an increase in the internal resistance of the battery and poor cycle stability of the battery.

In addition, zinc-iodine flow batteries mostly use ZnI 2 As electrolyte, but ZnI 2 It is easy to be oxidized by air to produce ZnO precipitation, and at the same time, in the process of high current density and long cycle, the I 2 Easy to precipitate, poor electrolyte stability, poor cycle stability of the battery, and the working current density is only 10mA / cm 2 , the power density of the battery is low

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