Salts ZEBRA

The molten salt, sodium aluminum chloride, fulfills two other tasks in the cell system. The ceramic electrolyte "-alumina is sensitive to high-current spots. The inner surface of the ceramic electrolyte tube is completely covered with molten salt, leading to uniform current distribution over the ceramic surface. This uniform current flow is one reason for the excellent cycle life of ZEBRA batteries. 

The molten salt electrolyte also contributes to the safety behavior of ZEBRA cells. The large amount of energy stored in a 700 g cell, which means about 30 kWh in a 300 kg battery, is not released suddenly as heat as be expected in a system with liquid electrodes such as the sodium sulfur cell. In the case of accidental destruction of ZEBRA cells, the sodium will react mainly with the molten salt, forming A1 sponge and NaCl. -The diffusion of the NaAICI ... 

Detonation of a Zebra Charge.. Accdg to Taylor (Ref 2), Paterson (Ref 1) has shown that intense illumination is emitted from granular common salt when it is placed in alternate... 

I l.ATE IX 1 holograph of a zebra charge, showing in-louse luminosity in salt zones... 

Such a battery was proposed for the first time by Yu et al. [475] and by Gray et al. [470], These batteries utilize the same pair of electrodes as the Zebra battery, Na/FeCl2, but the electrolyte is a room temperature molten salt, A1C13-MEIC-NaCl. Yu et al. [475] used this electrolyte with the following composition 47 45 8 mole%. Gray et al. [470] proposed the addition of HC1 to the electrolyte. The electrode reactions during discharge are... 

The Zebra Desalt Spin Columns that come with the DyLight Labeling Kits remove free dye. These columns contain a desalting resin and molecular weight cutoff. They perform well in desalting small sample volumes, providing excellent protein recovery and > 95% retention of small molecules and salts (<7 kDa). 

Finally, high-temperature molten salt electrolyte batteries (NaS, Zebra) require completely inorganic separators capable of withstanding liquid metal temperature and chemical attack, effectively acidic conditions at temperatures >200 °C. Beta-AlaOs has been significantly engineered to serve this role [10]. 

Small cracks in the ceramic electrolyte can be closed by formed salt and Al. When crack is larger, formed Al short-circuits between positive and negative electrode. This cell loses voltages, but still the whole system can be operated as long as failed cell was within 5-10 % of the total cells. The battery controller detects this and adjusts all operative parameters. In this meaning, ZEBRA battery is failure tolerant to some extent. 

The charge capacity of the ZEBRA cell is governed by the quantity of NaCl available in the positive electrode. During an operation, the liquid salt NaAlCU is a Na reserve as shown in the following reaction ... 

The ZEBRA battery comprises a NiCU positive electrode in a central compartment with NaCl salt, impregnated with NaAlCls, which is a liquid mixture of NaCl and AICI3 (considered to be a secondary electrolyte). The negative electrode is liquid sodium confined in a second, outer compartment. The wall separating the two compartments is made of a P alumina ceramic (or P-AI2O3), conductive of sodium ions, considered to be the primary electrolyte. The element is sealed hermetically and functions at temperatures equal to or higher than 300°C so that the active components remain in the liquid state. 

ZEBRA batteries use Ni power and plain salt for the electrode material the electrolyte and separator is jS"-Al203-ceramic, which is conductive for Na" ions but an insulator for electrons [4]. 

The cathode has a porous structure of nickel and salt which is impregnated with NaAlCU, a 50/50 mixture of NaCl and AICI3. This salt liquehes at 154°C, and in the liquid state it is conductive for sodium ions. It has the following functions, which are essential for ZEBRA battery technology ... 

This same reaction of the liquid salt and liquid sodium is relevant for the high safety standard of ZEBRA batteries In case of mechanical damage of the ceramic separator due to a crash of the car the two liquids react in the same way, and the salt and aluminum passivates the NiCb cathode. The energy released is reduced by about 1/3 compared to the normal discharge reaction of sodium with nickel chloride. 

ZEBRA cells are produced in the discharged state so that no metallic sodium can be handled. All the required sodium is inserted as salt. Figure 10.6 shows the cell design. The positive pole is connected to the current collector, which is a hair-needle shaped wire with an inside copper core for low resistivity and an outside nickel plating so that all material in contact with the cathode is consistent with the cell chemistry. 

Nowadays any product that is introduced to the market has to be recycled at the end of its usage. ZEBRA batteries are dismantled. The box material is stainless steel and Si02, both of which are recycled by established processes. The cells contain Ni, Fe, salt, and ceramic. For recycling they are simply added to the steel melting process of the stainless steel production. Nickel and iron are contributed to the material production and the ceramic and salt is welcome to form the slag. The recycling is certihcated and cost effective. 

Battery Recycling. The recycling options for ZEBRA batteries have been comprehensively studied The result is that very simple process has been developed the batteries are disassembled and then the cells are cut and put into a standard pyrometallurgical stainless-steel production process. The steel and nickel goes into the metal melt and the salt, aluminum chloride, and ceramic partition into the slag. 

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