Article

Fabrication of High-Aspect-Ratio Electrode Arrays for Three-Dimensional Microbatteries

Innovative Micro Technol., Santa Barbara
Journal of Microelectromechanical Systems (impact factor: 2.1). 09/2007; DOI:10.1109/JMEMS.2007.901638 pp.844 - 852
Source: IEEE Xplore

ABSTRACT Silicon-micromachining techniques have been combined with conventional material-synthesis methods to develop microelectrodes for 3-D microbatteries. The resulting electrodes feature an organized array of high-aspect-ratio microscale posts fabricated on the current collector to increase their surface area and volume for a given footprint area of the device. The diameter of the posts ranges from a few micrometers to a few hundred micrometers, with aspect ratios as high as 50. The fabrication approach is based on micromolding of the electrode materials and subsequent etching of the mold to release the electrode structures. Deep reactive-ion-etching or photo-assisted anodic etching has been used to form an array of deep holes in the silicon mold. Electroplating or colloidal-processing method has been used to fill the mold with battery-electrode materials. Measurements on electrochemical half-cells indicated that the 3-D electrode arrays, which are composed of vanadium oxide nanorolls or carbon, exhibited much greater energy densities (per-footprint area) than that of the traditional 2-D electrode geometries. The use of electroplating enabled us to fabricate 3-D interdigitated arrays of nickel and zinc; and battery operation was demonstrated. [2006-0293].

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Keywords

3-D electrode arrays
 
3-D microbatteries
 
battery-electrode materials
 
conventional material-synthesis methods
 
electrochemical half-cells
 
electrode materials
 
fabricate 3-D interdigitated arrays
 
given footprint area
 
greater energy densities
 
high-aspect-ratio microscale posts fabricated
 
hundred micrometers
 
microelectrodes
 
organized array
 
photo-assisted anodic etching
 
posts ranges
 
resulting electrodes feature
 
Silicon-micromachining techniques
 
subsequent etching
 
traditional 2-D electrode geometries
 
vanadium oxide nanorolls