Phosphoric Acid Distribution after Load Cycling at high Current Densities with Different Types of HT-PEM MEAs

Transcription

1 Phosphoric Acid Distribution after Load Cycling at high Current Densities with Different Types of HT-PEM MEAs Nadine Pilinski, Vietja Tullius, Dr. Wiebke Germer, Peter Wagner, Dr. Alexander Dyck Prague (Czech Republic) H 2 -Days 2016

2 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with different Types of MEAs Fuel Cell Performance Acid Distribution Summary 2

3 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with different Types of MEAs Fuel Cell Performance Acid Distribution Summary 3

4 NEXT ENERGY EWE Research Centre for Energy Technology System Modelling and Analysis Energy Systems System Solutions for the Energy Transformation Photovoltaics Integration of Thin-Film-Technology in Products Energy Storage Innovative Technologies for Stationary and Mobile Applications Fuel Cells Efficient Supply of Power and Heat 4

5 Fuel Cells - Research and Development Topics CHP Systems Evaluation, HEMS, System Integration Mobility Hybridisation, Hydrogen, Efficiency, Fuel Cell System Fuel Cells Efficient Supply of Power and Heat Head of Division: Dr. Alexander Dyck Characterisation Measurement Technology, Analytics, HT-PEM, Degradation Materials Electrochemistry, AEMFC, Membrane, Catalyst 5

6 EU-Project CISTEM CISTEM: Construction of Improved HT-PEM MEAs and Stacks for Long Term Stable Modular CHP Units Vision: Development of a new HT-PEMFC based CHP technology with high efficiency and long lifetime Proof viability of HT-PEMFC technology for large CHP systems Degradation investigations: single components, MEAs, stacks, CHP units Development Overview GA No: Duration: 1 st June st May

7 National Project QUALIFIX QUALIFIX national project Reduction of production-conditioned manufacturing losses and improvement of the long time stabilities by high-class optimisation in all production steps along the value chain of a mobile power supply unit, based on the HT-PEMFC technology components MEA stack system Duration: 1 st May st April

8 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with Different Types of MEAs Fuel Cell Performance Acid Distribution Summary 8

9 Experimental Setup HT-PEM test benches Anode: λ H 2 =1.5, Cathode: λ Air=2.0, T=160 C, p=1 atm, P c =0.75 MPa 9

10 Experimental Setup Product water collection cell unit anode water cell compression unit cathode water Anode: λ H 2 =1.5, Cathode: λ Air=2.0, T=160 C, p=1 atm, P c =0.75 MPa 10

11 Experimental Setup Test procedure over 500 hours A/cm A/cm 2 Daily IV curve OCV 1 A/cm 2 Anode: λ H 2 =1.5, Cathode: λ Air=2.0, T=160 C, p=1 atm, P c =0.75 MPa 11

12 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with Different Types of MEAs Fuel Cell Performance Acid Distribution Summary 12

13 Fuel Cell Performance MEA type 1 - BASF Voltage loss rate: BASF Celtec -P1100W MEA BASF Fuel Cell, Germany Active area: cm 2 95 wt% phosphoric acid 70 PA molecules per repeat unit GDL: woven carbon cloth Cathode: 0.75 mg Pt /cm 2 Anode: 1.0 mg Pt /cm 0.3 A/cm 2 : A/cm 2 : A/cm 2 : - 46 µv/h 13

14 Fuel Cell Performance MEA type 2 - DPS Voltage loss rate: Danish Power Systems Dapozol -G55 MEA Danish Power Systems, Denmark Nominal active area: 25 cm PA molecules per repeat unit GDL: non-woven carbon cloth Cathode/Anode: mg Pt /cm 0.3 A/cm 2 : A/cm 2 : A/cm 2 : µv/h 14

15 Fuel Cell Performance MEA type 3 - FMT Voltage loss rate: FuMA-tech fumea HTPEM FuMA-tech, Germany Nominal active area: 25 cm 2 Cathode: mg Pt /cm 0.3 A/cm 2 : A/cm 2 : A/cm 2 : µv/h 15

16 Fuel Cell Performance MEA type 4 - APM Voltage loss rate: Advent Advent PBI MEA (Formerly BASF P1100W) Advent, Greece Active area: cm 2 95 wt% phosphoric acid 70 PA molecules per repeat unit GDL: woven carbon cloth Cathode: 0.75 mg Pt /cm 2 Anode: 1.0 mg Pt /cm 0.3 A/cm 2 : A/cm 2 : A/cm 2 : - 80 µv/h 16

17 Comparison of Fuel Cell Performance Voltage loss rates of BASF-, DPS-, FMT- and APM-MEA DPS-MEA more sensitive to performance loss at higher load At higher current densities higher voltage loss rates High EASA loss of DPS-MEA compared to BASF, FMT and APM correlates with voltage loss rates of DPS 17

18 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with Different Types of MEAs Fuel Cell Performance Acid Distribution Summary 18

19 Phosphoric Acid Loss & Water Production Comparison of PA loss rate and water production High PA loss at begin and end of test Full characterization PA loss & water production primarily on cathode side In general, PA loss and water production constant over time 19

20 Acid Distribution & PA Loss Rates Acid distribution in MEA and product water MEA type PA MEA pristine [mg/cm 2 ] PA MEA EoT [mg/cm 2 ] PA cathode water [mg/l] PA anode water [mg/l] BASF (-40%) DPS (-38%) FMT (-40%) APM (-42%) PA loss rate calculated by product water Lower acid doping level of DPS-MEA Similar PA loss of MEAs Acid loss: BASF<DPS<FMT<APM Voltage loss rate cannot be coupled to acid loss other reasons (loss of EASA) 20

21 MEA Changes Weight, Acid and Thickness Comparison of MEA changes BoL and EoT Similar loss of weight, initial acid and thickness, but Low weight loss of DPS Lower acid doping level? High thickness loss of FMT-MEA Procedure of assembly? MEA-components? 21

22 MEA Changes Physiochemical Changes Physiochemical changes that can occur during acid leaching process Effect on membrane volume, thickness and area BPP GDL Membrane GDL BPP Compressed GDL Acid swelled membrane Uncompressed GDL Reduced swelled membrane BPP GDL Membrane GDL BPP GDL Membrane GDL GDL Membrane GDL DPS 220±7 µm GDL Cathode 230±10 µm 35±4 µm CL Cathode 26±9 µm 67±7 µm Membrane 48±10 µm 36±6 µm CL Anode 25±7 µm 252±16 µm GDL Anode 253±23 µm 22

23 Overview Introduction NEXT ENERGY EU-Project CISTEM National Project QUALIFIX Load Cycling Test with Different Types of MEAs Fuel Cell Performance Acid Distribution Summary 23

24 Summary Comparison of 4 types of MEAs: BASF, DPS, FMT, APM Fuel cell performance: DPS-MEA more sensitive to performance at higher load, probably not related to acid loss Voltage loss rates correlated with EASA loss Acid distribution: High PA loss at begin and end of test Full characterization PA loss & water production primarily on cathode side Similar percentage of PA loss of all MEAs High acid loss in product water APM-MEA MEA changes: Low weight loss of DPS and high thickness loss of FMT-MEA Reduced swelled membrane, uncompressed GDL 24

25 25

26 0.3 A/cm 2 - DPS Effective diameter increase, decrease of ionic conduction plot shifts away from the origin, (increase resistance to charge transfer) 26

27 Crossover & Resistance - DPS Reduction in volume, thickness and conductivity of membrane increase in the ohmic resistance, increase of contact resistance between MEA and BPPs 27

28 0.3 A/cm 2 all MEAs BASF FMT DPS APM 28