Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour Achieving high Pt utilization and superior performance of high temperature polymer electrolyte membrane fuel cell by employing low-Pt-content catalyst and microporous layer free electrode design Dongmei Yao a , Weiqi Zhang a , Qiang Ma a , Qian Xu a , Sivakumar Pasupathi b , Huaneng Su a,c,* a Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, PR China b South African Institute for Advanced Materials Chemistry, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa c Key Laboratory of Fuel Cell Technology of Guangdong Province, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, PR China HIGHLIGHTS • GDEs with low Pt loadings are developed for HT-PEMFC. • Combining low-Pt-content catalyst and MPL-free structure is a way to reduce Pt use. • The Pt loading can be lowered to 0.2 mg cm -2 and still with satisfactory performance. • Ultra-low Pt loading can be expected from this strategy by enhancing CL quality. ARTICLE INFO Keywords: High temperature polymer electrolyte membrane fuel cell Gas diffusion electrode Catalyst layer Low Pt loading Pt utilization Fuel cell performance ABSTRACT Reducing the platinum (Pt) use is of significance to popularize high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) since its average Pt loading in a typical gas diffusion electrode (GDE) normally reaches 0.7 mg cm -2 . In this work, an attempt to lower the Pt loading for the electrodes of HT-PEMFC is made by employing low-Pt-content catalysts (20 wt% and 10 wt% Pt/C) with the combination of microporous layer (MPL)-free electrode structure design, by which high Pt utilization and minimum ohmic/mass transfer re- sistances can be simultaneously maintained. Voltage loss mechanism and the catalyst layer (CL) morphologies of the GDEs are analyzed by polarization curve, electrochemistry impedance spectroscopy, cyclic voltammetry and scanning electron microscopy. The results show that the electrode Pt loading can be lowered to 0.2 mg cm -2 by this strategy but it still demonstrates a maximum Pt-specific performance of 1.6 W mg Pt -1 and an area-specific power density of 0.32 W cm -2 , which is a considerable improvement on developing HT-PEMFC with low Pt loading. There is a tradeoff between reducing Pt loading and increasing Pt utilization to maintain a superior CL quality, then ensuring that the fuel cell performance is fit for practical applications. 1. Introduction There is a trend to elevate the operating temperature of polymer electrolyte membrane fuel cell (PEMFC) to meet some challenges when it is with low temperatures, such as low CO tolerance and complex water management [1,2]. High temperature (HT) PEMFCs based on phosphoric acid (PA)-doped poly[2,2’-(m-phenylene)-5,5′-bibenzimi- dazole] (PBI) or poly[2,5-benzimidazole] (ABPBI) membranes are so far the most successful candidates in this field [3–5]. With motivated stu- dies in last two decades [6–16], the performances of HT-PEMFCs are approaching the level of low temperature PEMFCs based on Nafion membranes [17–19]. However, the use of high amount of Pt catalyst (normally between 0.5 and 1.2 mg cm -2 ) in this system is a main drawback from the perspective of real application [19–23]. Therefore, reducing the Pt use is of great significance for HT-PEMFCs being more competitive in this field. At present, only a few works were conducted to lower the Pt loading of the electrodes for HT-PEMFCs [24–29], and most of them were fo- cused on using advanced catalyst deposit techniques, such as ultrasonic spraying [24,28], electrospraying [29] and reactive spray deposition technology (RSDT) [27] to tailor the catalyst layer (CL) with superior pore structure and high Pt utilization, then decreasing the Pt loading of https://doi.org/10.1016/j.jpowsour.2019.04.045 Received 18 January 2019; Received in revised form 8 April 2019; Accepted 10 April 2019 * Corresponding author. Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, PR China. E-mail address: suhuaneng@ujs.edu.cn (H. Su). Journal of Power Sources 426 (2019) 124–133 0378-7753/ © 2019 Published by Elsevier B.V. T