Nano porous silicon for electricity storage

Low cost electricity storage is important to cope with the volatile nature of solar energy and wind energy. Crystalline Si is an attractive material not only for Si solar cells but also for storing electricity. It is known from the literature that Si nanostructures exhibit a ten-fold storage capacity for Li ions when compared with conventional graphite anodes. This project evaluates nano-structured porous Si as an anode for Li-ion batteries. The porous Si layers are prepared by an electro chemical etching procedure. The project aims at optimizing the electrochemical etching conditions for achieving a large and stable storage capacity. With the technological equipment available at ISFH (www.isfh.de) it will be possible to investigate new porous Si modifications. The candidate shall measure and model the interplay of the etching chemistry, the porous Si structure, and the storage performance. At ITC the candidate shall investigate the reaction steps for charging and discharging of porous nanostructures. The project will be co-supervised by a physicist and a chemist. 

 Figure 1: Scanning electron micrograph of a double layer of meso-porous silicon. The porosity of the top layer is 20 % and that of the bottom layer is 50 %