Chronoamperometric Investigations of the Electrode–Electrolyte Interface of a Commercial High Temperature PEM Fuel Cell

Abstract

This paper presents investigations into the chronoamperometric experiments performed on polybenzimidazole/phosphoric acid based high temperature polymer electrolyte membrane fuel cells. Electrolyte loadings in the membrane electrode assembly are varied to realise three different degrees of flooding of the electrode. Steady state as well as dynamic measurements at three different temperatures (160, 120 and 80 °C) is made via chronoamperometry on these cells. The transient current behaviour resulting from a voltage step change from open circuit voltage (∼1 V) to low voltages (0.1 V) are recorded and analysed. Analysis using the Cottrell plot depicts the underlying mass transport processes in the three different electrodes, catalyst utilisation as well as a better description of the three phase boundary reaction zone. An extension of the Cottrell equation is deduced to describe a regular commercial fuel cell behaviour.

Organometallic Complexes Anchored to Conductive Carbon for Electrocatalytic Oxidation of Methane at Low Temperature

“…With the use of the Randles-Sevcik equation, the diffusion coefficient of methane (shown in Figure B) was estimated at 3.19 × 10 –12 cm 2 s –1 (see Supporting information for detailed explanation on the calculation). The Cottrell plot produced from our measurements approaches the origin as has been previously described . This describes the two-phase boundary reaction zone where the methane permeates, dissolves into the electrolyte, and diffuses toward the electrode.…”

“…The Cottrell plot produced from our measurements approaches the origin as has been previously described. 44 This describes the two-phase boundary reaction zone where the methane permeates, dissolves into the electrolyte, and diffuses toward the electrode. For reference, the diffusion coefficient of hydrogen at the anode in hydrogen PEM fuel cell is only about 10 −2 cm 2 s −1 , 45 which indicates a major limitation to be overcome is the transport of methane to reach the reactive sites.…”

In situ investigation of dissociation and migration phenomena at the Pt/electrolyte interface of an electrochemical cell

“…Either excessive penetration of the PA into the WE (the so-called “flooding”), or the electrode drying have detrimental effects on the cell performance. 20 This work shows that the thickness of the PA layer on the Pt surface strongly depends on the electrode potential. Therefore, controlling the cell voltage (along with the temperature and humidity) in such a way that an optimum film thickness is maintained could be used as a means to increase the HT PEMFC performance.…”

“…While conventional diagnostic tools provide valuable information regarding the global performance of a fuel cell (such as current–voltage characteristics, cell resistance, etc. 20 ), they can only deliver indirect information on the PA distribution within a membrane-electrode assembly (MEA) under the operation conditions. Post-mortem analyses (porosimetry, acid-base titrations, gravimetric analyses 21 ) are usually used to analyze the PA distribution in a HT PEMFC.…”

Synthesis of In : SnO2/La4NiS7 via Diethyldithiocarbamate‐Assisted Spin Coating: A Promising Route for High‐Performance Transparent Photoelectrochemical Energy Storage and Generation

“…With the aid of a rate of alteration, the possible action's long-term effects are ChemistrySelect evaluated. [67] The I-t plot was located using the transitory approach. The molecules with electrochemical activity undergo transportation towards the surface of the dynamic electrode as a result of the connected voltage.…”