Silicon-microtube scaffold decorated with anatase TiO2 as a negative electrode for a 3D litium-ion microbattery

Abstract

An optimized scaffold based on silicon microtubes is designed to increase the surface capacity of 3D lithium-ion microbatteries. High-depth, mechanically robust microstructures are fabricated using microelectronic facilities. Conformal deposition of anatase TiO2 is achieved using atomic layer deposition, realizing the targeted improvement for microbatteries; a surface capacity of 0.2 mA h cm-2 at a charge rate of C/10 is obtained in standard liquid electrolyte. This work paves the way for the fabrication of solid-state 3D Li-ion microbatteries with an efficient 3D scaffold. A scaffold based on silicon microtubes is used to improve the volumetric capacity of a 3D Li-ion microbattery. It is fabricated using facilities compatible with CMOS (complementary metal-oxide semiconductor) technology. A surface capacity close to 0.2 mA h cm-2 is obtained in liquid electrolyte with the silicon-microtube scaffold (charge rate of C/10). The obtained performance values are compared to previously published results. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.