Alloy-based negative electrode materials have much higher specific capacity per weight and per volume than a conventional graphite-based material, but show very short cycle lives due to a large volume change during Li charge-discharge cycles. Tin based nano-composite alloys (Sn/Ag
3Sn) prepared by mechanical alloying method showed significantly improved cycle life because structure and phase changes could occur easily via intermediated ternary phases LiAg
2Sn/Li
2AgSn during charge-discharge process. Tin-based multi-layered plated electrodes (Sn/Cu
6 Sn
5 /Zn) prepared by electrochemical plating method also showed much improved cycle life. Silicon-based nano-composite films (Si/Ni,Cr,Nb,Fe) were also developed with improved cycle life. Nano-designing of materials would be very important for improving the cycle lives, keeping the high capacity.
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