Rapid Screening of Micro Fuel Cells for Portable Electronics PIs: Li Tan, Engineering Mechanics Zhaoyan Zhang, Mechanical Engineering University of Nebraska, Lincoln, NE 10/01/07

11/01/06-04/30/07 (also seen in previous report) Completed geometry and width design for micrometer channels; Started modeling aspects of micro fuel cells; Completed fabrication of individual channels with photolithography; Completed fabrication of micro fuel cell testing array; Completed fabrication of a testing sample with 4 cells. 05/01/07-09/30/07 Fabrication of micro fuel cell arrays Completed design of micro fuel cell arrays (8  8 cells); Completed design/fabrication of three masks for micro channels, inlet/outlet, and electrodes; Completed fabrication of micro channel arrays (4  4 cells) on Pyrex glass (1/4 wafer); Completed fabrication of inlet/outlet on Pyrex. Performance of Single Fuel Cell Two different electrolyte membranes (Nafion 117 and 202) were explored. A novel concept on electrocatalyst support Initiated a methodology to integrate nanoparticles into fuel cell research. Research Progress (11/01/06-09/30/07)

Completed 8  8 Fuel Cell Masks Mask I: in/outlets Channel 3 Mask III: Electrodes Fabricated In/outlets Mask II: Flow Channels

Completed Fuel Cell Array (4  4) 100 um Pyrex Mask 2 UV Pyrex Au Cr photoresist Au etching Cr etching HF etching Remove photoresist and Au/Cr Photoresist Chromium/Gold 4.8 – 49 wt% HF etching Fuel Cell Array Fabrication Process Flow

2  2 array was used as a base for fuel cell Two conducting membranes with different thicknesses were tested: –Nafion® 117 – 183  m –Nafion® 212 – 51  m Nafion® 212 presented better efficiency, as expected due to its thinner nature. Experimental Measurements of Single Fuel Cell

Nanoparticle (0 dimension)MicroFiber (1 dimension) Packed Particles (80 nm) Uniform  1.5  m Fiber Motivation: The surface areas of current catalyst supports are low, challenging to improve the fuel cell performance. Aim: 3D nanoporous catalyst support. A Novel Electrocatalyst Support

Summary and Future Work Confirmed (05/01/07-09/30/07): Fabrication of micro fuel cell arrays Completed design of micro fuel cell arrays (8  8 cells); Completed design/fabrication of three masks for micro channels, inlet/outlet, and electrodes; Completed fabrication of micro channel arrays (4  4 cells) on Pyrex glass (1/4 wafer); Completed fabrication of inlet/outlet on Pyrex. Performance of Single Fuel Cell Two different electrolyte membranes (Nafion 117 and 202) were tested. A novel concept on electrocatalyst support Initiated a methodology to integrate nanoparticles into fuel cell research. Work Plan (10/01/07-04/30/08): Explore optimum conditions for fuel cell operation Prepare a complete micro fuel cell array (8  8 cells) on Pyrex wafer (d~4”); Align and integrate in/outlets with flow channels and electrodes; Explore funding opportunities for the novel electrocatalyst support; Initiate I-V test for 64-cell.