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As listed in Table 1368, silicon (Si) alloying anodes provide theoretical capacities more than 10 times that of
intercalating anodes. However, during the alloying/de-alloying reactions, there is a volume expansion up to 300% in the Si alloying anodes. Such volume expansion can break up the electrode, resulting in reduced capacity and shorter cycle life of <200 cycles. Nano particle-Si, Si nano-wires, porous Si and Si graphite blends have recently been proposed to minimize the problems that are caused by volume expansion.
Table 1368. Comparison of the properties of some typical anodes.
|
LTO (lithium titanate oxide) |
Graphite |
Silicon |
Type |
Intercalation |
Intercalation |
Alloying |
Theoretical capacity mAh/g |
175 |
330 |
4200 |
Voltage vs Li/Li+ (V) |
1.5 |
0.1 |
0.1 |
Current collector |
Aluminium |
Copper |
Copper |
Main disadvantages |
Low voltage & low energy density cell |
Safety issues |
Volume expansion (up to 300%), poor cycling ability |
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