Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 18: Poster Session
MM 18.5: Poster
Montag, 31. März 2014, 18:00–20:00, P4
Nanostructured black silicon as anode for lithium-ion batteries — •Gibaek Lee1,2, Stefan L. Schweizer2, and Ralf B. Wehrspohn1,2 — 1Fraunhofer Institute for Mechanics of Materials, Halle, Germany — 2Martin-Luther-University Halle-Wittenberg, Halle, Germany
It has been known for some time past that silicon can incorporate large amounts of Li with a specific capacity of 4200 mAh/g, about a factor of 11 larger than for state of the art graphite anodes. However, silicon and silicon-based negative electrodes exhibit huge volume expansion (ca. 320%) during lithiation/delithiation, resulting in mechanical disintegration of electrode and rapid capacity fading. Therefore, relaxation of the stress caused by the expansion and contraction of Li-Si alloy materials is important to obtain a good cycleability. Furthermore, the formation of solid electrolyte interphase (SEI) induced by decomposition of electrolyte hinders lithium ion movement during the Li-Si alloying/de-alloying, resulting in poor capacity retention upon cycles. In this study, we prepared well-ordered nanostructured black silicon arrays (nb-Si) on silicon substrate by gas chopping technique. The electrochemical properties of the nb-Si electrode were systematically investigated. The material characteristics have been analyzed by CV, SEM and TEM. The performance of nb-Si electrode has been examined by galvanostatic charge/discharge cycling. In order to understand the correlation between surface condition and Li-Si alloying, we have investigated the surface composition of nb-Si electrode before and after pretreatment by means of high resolution XPS as well