Stable anodes for lithium ion batteries made of self-organized mesoporous silicon. (1st October 2015)

• Record Type: Journal Article
• Authors: Wolter, Sascha J; Köntges, Marc; Bahnemann, Detlef; Brendel, Rolf
• Is Part Of: Semiconductor science and technology. Volume 31:Number 1(2016:Jan.)
• Publication Date: 2015-10-01
• Subjects: mesoporous -- silicon -- lithium ion battery -- anode -- cycle lifetime -- self-organized; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/0268-1242/31/1/014007
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: Alloy-forming compounds, such as electrodes for lithium ion batteries, stand out in terms of their theoretical specific charge capacity while still lacking in mechanical stability due to significant volume changes during operation. Herein, we examine the approach of combining low structural dimensions of the active material with built-in expansion volumes and assess their benefit for silicon anodes in lithium ion batteries. Consequently, self-organized mesoporous silicon is prepared as a suitable anode material for lithium ion batteries without any pre-structuring methods. The anodes are made by employing electrochemical etching methods in a scalable process and are characterized by ellipsometry. Thermally evaporated copper is utilized as the current collector. A sheet of freestanding silicon in contact with copper is used as an anode material with a thickness of 3 μ m. After an initialization phase, electrochemical characterization reveals an anode stability of more than 160 cycles with a specific charge capacity of 730 mAh/g. The mechanical stability of the anode is examined by taking SEM measurements of the used electrode material.