Cycling Efficiency of Lithium Anode

Table 3). However, their cycle life depends on the discharge and charge currents. This problem results from the low cycling efficiency of lithium anodes. Another big problem is the safety of lithium-metal cells. One of the reasons for their poor thermal stability is the high reactivity and low melting point (180 °C) of lithium. 

There have been many attempts to improve the cycling efficiency of lithium anodes. We describe some of them below, by discussing electrolytes, electrolyte additives, the stack pressure on the electrode, composite anodes, and alternatives to the lithium-metal anode anode. 

Roberts M, Younesi R, Richardson W et al (2014) Increased cycling efficiency of lithium anodes in dimethyl sulfoxide electrolytes for use in Li-02 batteries. ECS Electrochem Lett 3 A62-A65. doi 10.1149/2.007406eel... 

Many studies have been undertaken with a view to improving lithium anode performance to obtain a practical cell. This section will describe recent progress in the study of lithium-metal anodes and the cells. Sections 3.2 to 3.7 describe studies on the surface of uncycled lithium and of lithium coupled with electrolytes, methods for measuring the cycling efficiency of lithium, the morphology of deposited lithium, the mechanism of lithium deposition and dissolution, the amount of dead lithium, the improvement of cycling efficiency, and alternatives to the lithium-metal anode. Section 3.8 describes the safety of rechargeable lithium-metal cells. 

Figure 7 Charge-discharge cycling efficiency of lithium metal anode at 0.5 mA cnT2...

As the cycling efficiency of metallic lithium is always significantly below 100% ( 99%), the lithium anode has to be overdimensioned (200-400%) in practical cells. 

Figure 6. Lithium cycling efficiency of composite lithium anodes in an Li/a -V205 coin-type cell (thickness 2 mm, diameter 23 mm) with 1.5 mol L 1 LiAsF6 - EC/2MeTHF. ...

To use these metals, they must have a deposition potential inside the electrochemical window of the electrolyte used. Aluminum cannot be deposited in basic melts, but it is reversibly deposited and stripped in acidic electrolytes, and it has excellent cycling efficiencies [459], Lithium appears to be the most attractive anode material, and aluminum is the second choice. Likewise sodium is attractive because of its lower cost than lithium. The A1C13-MEIC melts have a relatively high electrical conductivity at room temperature [466], 0.035 S cm-1. 

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... 

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