There is great interest in developing rechargeable lithium batteries with higher energy capacities and a longer cycle lifetimes. Silicon has very high lithium ion capacity of 4200 mAh/g, and has been suggested as a potential high capacity lithium battery anode material. However, it has been encumbered with serious expansion/ contraction during cycling, increasing internal resistance and resulting in cell failure. Severe silicon pulverization can be triggered by a large volume change (>300%) during lithium alloying (to form LixSi) and de-alloying (to reform Si), which results in electrically disconnected smaller particles. These disconnected particles cause a rapid decrease in cycling stability.  Porous silicon structures have been suggested as a potential means to accommodate silicon expansion/contraction while maintaining continuity. We will report on our fabrication of a nanoporous silicon structure by electrochemical etching process. We find that the specific capacity of the battery cell after 1000 cycles with a capacity of 1000 mAh/g.

Application of porous silicon particulates for lithium ion batteries

247th National Meeting (2014)

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