Protected lithium electrode

In a basic electrolyte with a protected lithium electrode [5]. 

Lithium-Air Batteries Using Protected Lithium Electrodes... 

The protected lithium electrode was originally developed for the aqueous Li-air cell. The discharge product is LiOH and forms by consuming both oxygen and water. Addition of excessive water in the electrolyte will lead to reduced specific energy of the total battery. A flow cell conflguration has been proposed to address this problem, in which there is continuous circulation of the electrolyte [54]. LiOH... 

The deposition points on the lithium electrode are the points at which the protective film has a higher lithium-ion conductivity. One example of these deposition points are the pits on the lithium anode caused by discharge. Crystalline defects and the grain boundaries in lithium may also initiate deposition. 

As lithium does not deposit uniformly for the reason mentioned above, mechanical stress is created in the lithium electrode under the protective film. 

The superiority of LiAsF6 in ether based solvents (2-Me-THF, THF, MeF) at lithium electrodes is an example of the formation of useful protecting films (As, Li2 As, Li (AsFv) allowing uniform lithium deposition [195], According to Aur-bach and co-workers, LiAsF6/2 - Me -THF is a highly suitable electrolyte for rechargeable lithium batteries. However, as 2-Me-THF is one of the least reactive sol-... 

The corrosion resistance of lithium electrodes in contact with aprotic organic solvents is due to a particular protective film forming on the electrode surface when it first comes in contact witfi tfie solvent, preventing further interaction of the metal with the solvent. This film thus leads to a certain passivation of lithium, which, however, has the special feature of being efiective only while no current passes through the external circuit. The passive film does not prevent any of the current flow associated with the basic current-generating electrode reaction. The film contains insoluble lithium compounds (oxide, chloride) and products of solvent degradation. Its detailed chemical composition and physicochemical properties depend on the composition of the electrolyte solution and on the various impurity levels in this solution. 

Solvents were initially selected primarily on the basis of the conductivity of their salt solutions, the classical example being propylene carbonate (PC). However, solutions based on PC on its own were soon found to cause poor cyclability of the lithium electrode, due to uncontrolled passivation phenomena. Solvent mixtures or blends were therefore developed and selection currently focuses on a combination of high dielectric solvents (e.g. ethylene carbonate, EC) with an alkyl carbonate (e.g. dimethy(carbonate, DMC), to stabilize the protective passivation film on the lithium electrode, and/or with a low viscosity solvent [e.g. 1,2-dimethoxyethane (DME) or methyl formate (MF)], to ensure adequate conductivity. 

The main problem arose with respect to the negative electrode. Complications typical for galvanic practice appear under its charge, that is, under cathodic deposition of lithium. As pointed out in Chapter 11, the surface of lithium in aprotic electrolytes is covered by a passive film (SEI) because of the chemical interaction with the components of electrolyte the organic solvent and anions. This film has the properties of solid electrolyte with conductivity by lithium ions. The film is sufficiently thin (its thickness does not exceed several nanometers) and it protects lithium safely from... 

Visco SJ, Nimon E, Jonghe LD (2010) Next generation Li-Air and Li-S batteries based on ceramic protected li electrodes The 15th international meeting on lithium batteries. Abstract 831... 

Netrhold S, Vaughey JT, Gnrggcr C, Lopez CM (2014) Errhancement in cycle life of metalUc lithium electrodes protected with Fp-silanes. J Powta- Sources 254 241-248. doi 10.1016/j. jpo wsotrr.2013.12.057... 

A gamet-type lithium-ion conducting solid electrolyte is another candidate for the protective layer of a water-stable lithium electrode. In 2007, Weppner and... 

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