Lithium anode reaction

The cathodic reaction is the reduction of iodine to form lithium iodide at the carbon collector sites as lithium ions diffuse to the reaction site. The anode reaction is lithium ion formation and diffusion through the thin lithium iodide electrolyte layer. If the anode is cormgated and coated with PVP prior to adding the cathode fluid, the impedance of the cell is lower and remains at a low level until late in the discharge. The cell eventually fails because of high resistance, even though the drain rate is low. 

Good results are obtained with oxide-coated valve metals as anode materials. These electrically conducting ceramic coatings of p-conducting spinel-ferrite (e.g., cobalt, nickel and lithium ferrites) have very low consumption rates. Lithium ferrite has proved particularly effective because it possesses excellent adhesion on titanium and niobium [26]. In addition, doping the perovskite structure with monovalent lithium ions provides good electrical conductivity for anodic reactions. Anodes produced in this way are distributed under the trade name Lida [27]. The consumption rate in seawater is given as 10 g A ar and in fresh water is... 

Lithium metal is chemically very active and reacts thermodynamically with any organic electrolyte. However, in practice, lithium metal can be dissolved and deposited electrochemically in some organic electrolytes [5]. It is generally believed that a protective film is formed on the lithium anode which prevents further reaction [6, 7]. This film strongly affects the lithium cycling efficiency. 

It is generally considered that the lithium surface film is produced by a reaction between the lithium and the electrolyte materials. However, by XPS we have detected vanadium on a lithium anode surface cy-... 

It is now well established that in lithium batteries (including lithium-ion batteries) containing either liquid or polymer electrolytes, the anode is always covered by a passivating layer called the SEI. However, the chemical and electrochemical formation reactions and properties of this layer are as yet not well understood. In this section we discuss the electrode surface and SEI characterizations, film formation reactions (chemical and electrochemical), and other phenomena taking place at the lithium or lithium-alloy anode, and at the Li. C6 anode/electrolyte interface in both liquid and polymer-electrolyte batteries. We focus on the lithium anode but the theoretical considerations are common to all alkali-metal anodes. We address also the initial electrochemical formation steps of the SEI, the role of the solvated-electron rate constant in the selection of SEI-building materials (precursors), and the correlation between SEI properties and battery quality and performance. 

OCV conditions, by a newly formed SEI is expected to be a slow process. The SEI is necessary in PE systems in order to prevent the entry of solvated electrons to the electrolyte and to minimize the direct reaction between the lithium anode and the electrolyte. SEI-free Li/PE batteries are not practical. The SEI cannot be a pure polymer, but must consist of thermodynamically stable inorganic reduction products of... 

With regard to rechargeable cells, a number of laboratory studies have assessed the applicability of the rocking-chair concept to PAN-EC/PC electrolytes with various anode/cathode electrode couples [121-123], Performance studies on cells of the type Li°l PAN-EC/PC-based electrolyte lLiMn20 and carbon I PAN-EC/PC-based electrolyte ILiNi02 show some capacity decline with cycling [121]. For cells with a lithium anode, the capacity decay can be attributed mainly to passivation and loss of lithium by its reaction with... 

It was recognized that this dendrite problem could not be solved without completely changing the negative electrode. Instead of electrodepositing metal, the anode reaction of choice was found to be storage of lithium in compounds with chemical potentials of lithium being very close to the pure Li metal. 

The battery consists of a lithium anode and a carbon paste cathode. The electrolyte consists of a solution of LiAlCl in thionyl chloride. The anode reaction is metal dissolution ... 

Along with the anode reaction, the so-called anode effect, a phenomenon often observed in fused salt electrolysis (see Chapter 4), may occur. In the present case, it may be due to a surface film of the type CVX formed on the anode material. This film on the one hand protects the carbon against destruction (and is the reason for high anodic overpotentials) in normal operation and, on the other hand, under more or less known conditions may block electron transfer completely. These conditions depend strongly on the electrolyte composition (purity) [46,47]. Additives, such as lithium fluoride, may be helpful in preventing the anode effect by wetting the electrode material. 

Lithium aluminates are also important in the development of molten carbonate fuel cells (MCFC) [82, 83], In these fuel cells, a molten carbonate salt mixture is used as an electrolyte. These fuel cells operate through an anode reaction, which is a reaction between carbonate ions and hydrogen. A cathode reaction combines oxygen, C02, and electrons from the cathode to produce carbonate ions, which enter the electrolyte. These cells operate at temperatures of 650°C and the electrolyte, which is usually lithium and potassium carbonate, is suspended in an inert matrix, which is usually a lithium aluminate. 

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