Carbon overall battery reaction

Lithium manganese oxide (Li-Mn02) battery is the most common consumer grade battery that covers about 80 % of the lithium battery market. This system includes heat-treated Mn02 as cathode, lithium metal as anode and LiC104 in propylene carbonate/dimethoxyethane as aprotic electrolyte. The overall battery reaction is ... 

Similar designs have been used in lithium chloride batteries, which operate at a temperature of 650°C. The cell has the form Li (liq.)/LiCl (liq.yClj (g), carbon.The two electrodes, the liquid lithium anode and the porous carbon anode in which the chlorine gas is fed imder pressure, are separated by a molten lithimn chloride electrolyte. The overall cell reaction is... 

One heavily studied battery system is the aluminum-air battery in which oxidation occurs at an aluminum anode and reduction at a carbon-air cathode. The electrolyte circulated through the battery is NaOH(aq). Because it is in the presence of a high concentration of OH , Al produced at the anode forms the complex ion [Al(OH)4] . The operation of the battery is suggested by Figure 19-19. The half-cell reactions and the overall cell reaction are... 

A schematic charge-discharge processes and the overall reaction of a lithium-ion battery using carbon (neg-... 

This type of Li battery has already widely diffused in the electronic consumer market, however for automotive applications the presence of a liquid electrolyte is not considered the best solution in terms of safety, then for this type of utilization the so-called lithium polymer batteries appear more convenient. They are based on a polymeric electrolyte which permits the transfer of lithium ions between the electrodes [21]. The anode can be composed either of a lithium metal foil (in this case the device is known as lithium metal polymer battery) or of lithium supported on carbon (lithium ion polymer battery), while the cathode is constituted by an oxide of lithium and other metals, of the same type used in lithium-ion batteries, in which the lithium reversible intercalation can occur. For lithium metal polymer batteries the overall cycling process involves the lithium stripping-deposition at the anode, and the deintercalation-intercalation at the anode, according to the following electrochemical reaction, written for a Mn-based cathode ... 

The uniqueness and versatility of carbonaceous porous materials is demonstrated by Mukai et al. (2004) in their attempt to reduce the phenomenon of irreversibility of the LIB. As indicated above, irreversibility is associated with the formation of solid electrolyte films on surfaces of carbons by an irreversible reaction of lithium ions with the electrolytes. For the isotropic porous carbons (not amorphous carbons as quoted by Mukai et al., 2004), the electrolyte film is formed preferentially in the entrances to the porosity (mainly microporosity). Should it be possible to prevent this deposition, then the irreversible component of battery performance could be reduced. It is established that increasing the heat treatment of carbons (normally beyond about 800 °C) decreases the pore dimensions, but at the same time there is reduction in volume of porosity which is available for lithium entry. Quite separately, Suzuki et al. (2003) report on the impossibility of bringing about a meaningful reduction in the irreversible component, maintaining the reversible component, by changing the porosity of the material. That is, an improvement automatically creates a deterioration. The use of an approach of carbon vapor deposition (as for pyrolytic carbons) has been tried whereby carbon is deposited in the entrances to the microporosity. There is no overall change to carbon structure. This method was successful but applications on an industrial scale are expensive. 

Because carbon is the limiting factor, the carbon conversion to methanol, also referred to as carbon efficiency, is an important operating parameter for overall ener efficiency. Carbon efficiency is a measure of how much carbon in the feed is converted to methanol product. There are two commonly used carbon efficiencies, one for the overall plant and one for the methanol synthesis loop. For the overall plant all the carbon-containing components in the process feedstock from the battery limits and the methanol product from the refining column are considered. For a typical plant and natural gas feedstock, an overall carbon efficiency is about 75%. The methanol synthesis loop carbon efficiency for the same plant is about 93%. The synthesis loop carbon efficiency is calculated using only the carbon in the reactive components in the makeup gas (CO and C02). Carbon in the form of methane is not considered because it is inert in the methanol synthesis reaction and is ultimately purged from the loop and burned. The carbon in the product for this calculation is that in the form of methanol in the crude leaving the methanol synthesis loop. 

Ion batteries. In the commonly used LiPFe-alkyl carbonate solutions, the surface films formed on the an( es may be dominated by solvent reduction, while the surface films formed on the cathodes may be dominated by LiF formation due to reactions of I MOy with HF. Thereby, the overall impedance of Li-ion batteries may be determined mostly by the cathode s surface resistance (due to its coverage by highly resistive LiF films). Upon cycling, the impedance of both anodes and cathodes may change ... 

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