Abstract: A proton exchange membrane fuel cell (PEMFC) possesses several advantages such as high energy density, low operating temperature, and fast startup, which make PEMFC the most promising and attractive candidate for electric vehicles and portable power. However, operations of fuel cells in the application of these systems are dynamic, and the transient behavior happens when the load changes. Transient operations may result in the oxidant starvation due to gas response rate lagging the loading rate, which will affect the durability and reliability of fuel cells further. In this paper, polyaniline (PANI) as a supercapacitor material was hybridized with a PEMFC catalyst in the electrode in order to buffer the load. PANI was synthesized by the chemical method using sulfide acid as the dopant. The PANI-Pt/C catalyst was prepared by mixing PANI and Pt/C in ultrasound and drying in air. The cyclic voltammetry of 10%PANI-Pt/C demonstrates that PANI can effectively improve oxygen reduction rate. The fuel cell performance is also improved by PANI according to the single fuel cell polarization experiment. The dynamic respondence of voltage to current and the multi-potential step chronoamperometry show that PANI can buffer and stabilize the voltage during the transient current loading and working at a large current.

Key words: proton exchange membrane fuel cell, dynamic respondence, polyaniline