Coulombic efficiency lithium battery electrodes

The coulombic efficiency of MAG electrode is 91.6% (irreversible capacity 33 Ah/ kg) for the first cycle, 99.2% for the second cycle, and it almost reaches an ideal value of 100% after the fifth cycle. In general, the coulombic efficiency of carbon anodes in the first cycle is so low that there exists a high irreversible capacity. Since this irreversible capacity of carbon anode does not contribute to the discharge capacity of lithium-ion battery, it is desirable to make it as low as possible in the viewpoint of increasing the battery capacity. It is known that the irreversible... 

Lopez, M. C., Ortiz, G. F., Lavela, R, Alcantara, R, and Tirado, J. L. (2013]. Improved coulombic efficiency in nanocomposite thin film based on electrodeposited-oxidized FeNi-electrodes for lithium-ion batteries,/. Alloys Compounds, 557, pp. 82-90. 

Arie et al. [116] investigated the electrochemical characteristics of phosphorus-and boron-doped silicon thin-film (n-type and p-type silicon) anodes integrated with a solid polymer electrolyte in lithium-polymer batteries. The doped silicon electrodes showed enhanced discharge capacity and coulombic efficiency over the un-doped silicon electrode, and the phosphorus-doped, n-type silicon electrode showed the most stable cyclic performance after 40 cycles with a reversible specific capacity of about 2,500 mAh/g. The improved electrochemical performance of the doped silicon electrode was mainly due to enhancement of its electrical and lithium-ion conductivities and stable SEI layer formation on the surface of the electrode. In the case of the un-doped silicon electrode, an unstable surface layer formed on the electrode surface, and the interfacial impedance was relatively high, resulting in high electrode polarization and poor cycling performance. 

The coulombic efficiency of Li-Al/FeS cells is controlled by the lithium activity of the negative electrode and the rate at which dissolved lithium can diffuse across the separator to the positive electrode. Typically this rate is only 0.1 to 0.2 mA/cm at 425°C. This low self-discharge rate leads to high coulombic efficiency. Similarly, the low impedance of bipolar cells (0.5 to 0.7 ft cm ) leads to high voltaic efficiency. Overall the major source of inefficiency is the heat loss associated with high-temperature operation. Development of a highly efficient thermal enclosure is necessary for aU high-temperature batteries. 

Since both neutral and reduced forms of (CH) have good stability in a battery employing lithium perchlorate in tetrahydrofuran solvent, a cell was constructed using the above polymer electrodes. It is the first stable, fully polymer, rechargeable battery with Coulombic efficiencies greater than 99%. A cell of this type, using 7% doped anode, has an open-circuit potential of 1 V and current of approximately 30 Am of (CH). ... 

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