Increasing fuel cell durability during prolonged and intermittent fuel starvation using supported IrOx
Increasing fuel cell durability during prolonged and intermittent fuel starvation using supported IrOx
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DOI：
10.1016/j.jpowsour.2021.229568
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发表时间：
2021-04
影响因子：
9.2
通讯作者：
Tita Labi;François B. Van Schalkwyk;S. M. Andersen;P. Morgen;S. Ray;J. Chamier
中科院分区：
文献类型：
--
作者：
Tita Labi;François B. Van Schalkwyk;S. M. Andersen;P. Morgen;S. Ray;J. Chamier
添加析氧反应（OER）催化剂是一种缓解燃料不足引起的潜在逆转影响的材料方法。在该研究中，将负载在石墨化Vulcan（GV）黑（56重量% Ir）上的氧化铱（IrOx）作为OER催化剂添加到膜电极组件（MEA）的阳极中（0.1mgIr/cm 2）。当暴露于间歇性5分钟、10分钟和30分钟的饥饿，并有10分钟的恢复期时，反向电池电位被钳位在−0.8 V，减轻了严重的碳降解。间歇性饥饿的MEA恢复>95%的其初始性能。在第一次事件之后，随着欧姆电阻的增加，性能损失为4%（0.2A/cm 2），此后性能保持相对稳定。利用SEM和EIS，增加的欧姆电阻归因于膜的变形和收缩以及离聚物重构，其影响质子传导路径。阳极变薄是不可避免的，这会导致接触电阻和性能下降。Pt和IrOx/GV催化剂在经受多次短时间燃料饥饿时保持相对稳定。IrOx/GV MEA是可逆耐受的，并且提供了对在周期性和长时间燃料饥饿期间发生的降解过程的深入了解。
Addition of an oxygen evolution reaction (OER) catalyst is a materials approach to mitigate the impacts of potential reversal caused by fuel starvation. In this study Iridium oxide (IrOx) supported on graphitized Vulcan (GV) black (56 wt% Ir) was added as an OER catalyst into the anode of a membrane electrode assembly (MEA) (0.1 mgIr/cm2). When exposed to intermittent 5-, 10- and 30- minutes of starvation, with 10 min recovery periods, the reversed cell potential was clamped at −0.8 V, mitigating severe carbon degradation. The intermittently starved MEAs regained >95% of their initial performance. After the first event, the performance loss was significant at 4% (0.2 A/cm2) with increases in ohmic resistance, thereafter the performance remained relatively stable. Using SEM and EIS, the increased ohmic resistance was attributed to deformation and contraction of the membrane and ionomer reconfiguration which impacted proton conductive pathways. Thinning of the anode was unavoidable, contributing to contact resistance and decreased performance. The Pt and IrOx/GV catalyst remained relatively stable when subjected to multiple short periods of fuel starvation. The IrOx/GV MEA was reversal tolerant and provided insight into the degradation processes which occur during periodic and prolonged fuel starvation.