Degradation Investigation of Electrocatalyst in Proton Exchange Membrane Fuel Cell at a High Energy Efficiency.

Jie Song,Meiling Dou,Kun Wang,Zhiyuan Guo,Qing Ye

doi:10.3390/molecules26133932

Abstract

The development of high efficient stacks is critical for the wide spread application of proton exchange membrane fuel cells (PEMFCs) in transportation and stationary power plant. Currently, the favorable operation conditions of PEMFCs are with single cell voltage between 0.65 and 0.7 V, corresponding to energy efficiency lower than 57%. For the long term, PEMFCs need to be operated at higher voltage to increase the energy efficiency and thus promote the fuel economy for transportation and stationary applications. Herein, PEMFC single cell was investigated to demonstrate its capability to working with voltage and energy efficiency higher than 0.8 V and 65%, respectively. It was demonstrated that the PEMFC encountered a significant performance degradation after the 64 h operation. The cell voltage declined by more than 13% at the current density of 1000 mA cm−2, due to the electrode de-activation. The high operation potential of the cathode leads to the corrosion of carbon support and then causes the detachment of Pt nanoparticles, resulting in significant Pt agglomeration. The catalytic surface area of cathode Pt is thus reduced for oxygen reduction and the cell performance decreased. Therefore, electrochemically stable Pt catalyst is highly desirable for efficient PEMFCs operated under cell voltage higher than 0.8 V.

Highlights

To mimic the operation of Proton exchange membrane fuel cells (PEMFCs) at a cell voltage higher than 0.8 V, so that the efficiency exceeds 65%, the operating current density was set at 80 mA cm−2
The durability of PEMFC was evaluated by constant-current operation for 64 h (Figure 1a)
We have evaluated the durability behavior of a single PEMFC at a high energy efficiency that operates at a voltage higher than 0.8 V and elucidated the material degradation as characteristic

Summary

Introduction

Proton exchange membrane fuel cells (PEMFCs), as clean and efficient energy conversion devices, have attracted much attention for their promising application in transportation and stationary power plants [1,2]. The large-scale commercialization of PEMFCs is still hindered by the high operating costs, mainly due to the low fuel economy and unsatisfied durability [3,4,5,6]. Fuel cell energy efficiency is defined as the ratio of output power to the consumed hydrogen enthalpy. For low temperature PEMFCs, the theoretical energy efficiency is about 83%, calculated by dividing the high heating value of hydrogen (286 kJ mol−1 ) by the Gibbs free energy of fuel cell reaction (237 kJ mol−1 ). The favorable operation conditions of PEMFCs are with single cell voltage between 0.65 and

Methods

Results

Conclusion