ISBN 9783843957472

978-3-8439-5747-2, Reihe Elektrotechnik

Andam Deatama Refino
Silicon nanowire anodes for lithium-ion microbatteries

214 Seiten, Dissertation Technische Universität Braunschweig (2026), Softcover, A5

Zusammenfassung / Abstract

The increasing demand for miniaturized autonomous electronic systems requires on-chip energy storage technologies with high energy and power densities that are compatible with standard microfabrication processes. Silicon (Si)-based lithium-ion microbatteries (micro-LIBs) are promising candidates due to its high theoretical specific capacity. However, their performance is limited by planar architectures and the mechanical instability of Si anodes.

To address these challenges, three-dimensional (3D) vertically aligned Si nanowire (SiNW) arrays were developed using top-down nanofabrication techniques, namely, cryogenic deep reactive ion etching (cryo-DRIE) and metal-assisted chemical etching (MACE). Electrochemical characterization in half-cell configurations revealed that SiNW anodes significantly outperform planar Si, exhibiting higher areal capacity, Coulombic efficiency, rate capability, and cycling stability. Increasing SiNW height further enhances areal capacity. Post-mortem analyses confirm that SiNW structures maintain structural integrity upon cycling. Pre-lithiation and carbon coating were investigated as performance enhancement strategies. While pre-lithiation improves initial efficiency, non-uniform lithiation in dense SiNW arrays remains a limitation. Carbon coating enhances initial capacity and stability yet degrades during prolonged cycling.

Overall, this work demonstrates that top-down-fabricated SiNW anodes are a promising platform for high-performance micro-LIBs and provides insight into the relationship between nanostructure design, fabrication, and electrochemical behavior.