| The goal of fabricating three-dimensional (3D) microbatteries is to improve upon the performance of 2D microbatteries or thin-film batteries by reconfiguring existing materials in a more advanced architecture. 3D battery architectures offer a new approach for miniaturized power sources. These batteries are designed to have a small areal foot print and yet provide sufficient power and energy density to operate autonomous MEMS devices. The more convenient approaches for fabricating such batteries are based on micromachining techniques such as electrodeposition of high aspect ratio metal rods in an array configuration.; Three types of three-dimensional microbatteries were fabricated and characterized: Ni-Zn, zinc-air, and Ag-Zn. These different types of microbatteries use different chemistries but all have the common feature of an out-of-plane array of micro-post electrodes. A 3D Ni-Zn microbattery was fabricated and demonstrated proper charge-discharge behavior for the first few cycles. The development of 3D zinc-air microbattery showed high discharge capability under various discharge conditions. Furthermore, performance of 3D zinc-air microbattery was demonstrated by successfully powering an electronic device. During discharge, the 3D zinc-air microbattery exhibited an electrode reaction which formed hollow ZnO electrodes by the Kirkendall effect. This electrode reaction strongly supports the functionality of the 3D microbattery. The fabrication of the Ag-Zn microbattery was accomplished by Ag electrode formation, separator coating, and Zn sedimentation. Due to imperfections in the separator coating, the 3D Ag-Zn microbattery had electrical shorts. |
