Electric storage in de-alloyed Si-Al alloy ribbons

Abstract

The capacitance of de-alloyed Si 1xAl x (x=0.2, 0.3, and 0.4) alloy ribbons with resistivities of 1-1000Ωcm was measured as a function of frequency between 1mHz and 1MHz from electric charge/discharge pulse curves of 10V applied at 100ms-25ns intervals, respectively, using an exponential transient analysis for electric charging/discharging. The capacitance of the de-alloyed Si-20 at.%Al specimen obtained by prompt charging/discharging decreased logarithmically from 102μF (0.55F/cm 3) to 1.2pF (53nF/cm 3) as frequency increased from 1mHz to 1MHz. From the observed electrode distance dependence on capacitance and nonlinear electronic transport behaviour, we deduced that the alloy consisted in a distributed constant equivalent circuit (series with 1.7% parallel), analogous to electric double-layer capacitors. © Copyright EPLA, 2012.