Well Controlled Array of Si Nanopillar with Metal Core as Negative Electrode for Lithium Ion Batteries

A promising Si negative electrode, that is a well controlled array of Si nanopillar, was fabricated by a semiconductor process. The electrochemical property of this electrode was examined by charge-discharge measurements, SEM and TEM observations. Although the result of charge-discharge measurements of this Si nanopillar electrode was comparable to those of a flat thin film Si electrode, pulverization of the Si film was successfully suppressed in the Si nanopillar electrode. In the Si thin film electrode, only the upper half of the Si film seemed to have reacted, and this caused cracking and pulverization. By contrast, in the Si nanopillar electrode, the entire Si film seemed to have reacted, and cracking and pulverization were suppressed. The experimental results demonstrated that the Si nanopillar electrode has a suitable structure for a Si negative electrode.