A novel proton-exchange porous silicon membrane production method for μDMFCs.

Meltem Gör Bölen,Tevhit Karacali

doi:10.3906/kim-2002-32

Abstract

This study introduces a new production method to use as a porous silicon-based proton exchange membrane for μDMFCs. In this respect, EIS, fuel crossover test, and fuel cell performance test at the μDMFC sample cell are performed at room temperature on a porous silicon-based membrane that was produced for passive mode μDMFC as a proton exchange membrane. The reason for performing the fuel crossover test is to ensure the silicon opened pores along the silicon wafer and to examine the fuel permeability of the membrane. The fuel crossover test shows that the fuel cell provides energy for about 60 min with a 50 mL fuel. EIS reveals proton permeability of proton exchange membrane. The calculated value of the conductivity of the membrane is 0.0016 S/cm. OCV of the system is 0.4V, whereas values (with highest power density is 0.1 mW/cm²and with the highest current density is 0.39 mA/cm²) are low. However, porous silicon is not a natural proton conductor. Hence, these values can be increased by different ways such as porous silicon functionalized, or serial connection of fuel cells. On the other hand, the value of OCV is consistent with the previous studies. In sum, this study presents a simple, cost-effective, and short time-consuming method for the production of porous silicon as proton-conducting membrane behavior.

Highlights

In the last century, the total production of energy from fossil fuels has increased rapidly, leaving fossil fuel reserves depleted
The main steps of the fabrication process that covers some activities such as KOH etching, the Cr/Au thin film deposition, the photolithography method used for masking, inductively coupled plasma (ICP), deep reactive ion etching (DRIE) and RIE methods used to ensure that the pore ends are opened, require a long time and include parameter-dependent methods
In order to eliminate these issues; this study presents a new method of porous silicon membrane production that was made for the use of as a membrane at passive mode direct methanol fuel cells

Summary

Introduction

The total production of energy from fossil fuels has increased rapidly, leaving fossil fuel reserves depleted. Another study [15] reported various performance tests of acid loaded porous silicon membrane based micro fuel cells under various parameters and conditions (molarity, thickness). Another study [16] examined the performance of an acid loaded porous silicon membrane for micro-fuel cells by following similar fabrication process in a different order. The main steps of the fabrication process that covers some activities such as KOH etching, the Cr/Au thin film deposition, the photolithography method used for masking, ICP, deep reactive ion etching (DRIE) and RIE methods used to ensure that the pore. Fuel crossover To prove that the produced porous silicon works as a membrane, 2 main measurements that are fuel crossover test and electrochemical impedance spectroscopy have performed. Between the 2 electrodes, a signal with an amplitude of 400 mV in the frequency range from 20 Hz to 10 kHz was applied at 25 °C and the Nyquist Z plot obtained with the measurement results using the EDC-1630 digital LCR meter for proton conductivity

Results and discussion

Fuel cell performance

Conclusions