A Framework for the Relationships between Stability and Functional Properties of Electrochemical Energy Materials

Abstract

The path toward a renewable energy future relies on the development of materials for electrochemical energy technologies that are not only highly functional but also stable. In this Perspective, we will discuss a framework for the relationships between function and stability, starting by revisiting how we measure stability that should focus on changes to the nature and number of active centers (materials stability) together with monitoring how current/potential change over time during operation (reaction durability). By shifting our focus to materials properties, we then discuss how subtractive and additive processes such as dissolution, deposition, and (de)intercalation contribute to changes in the local surface composition, coordination environment, and phase restructuring that accompany the degradation of electrochemical materials. Ultimately, gaining insights into the processes responsible for changes to active centers during operation will help us better predict and control the durability of materials for clean energy.

Operando Fe Dissolution in Fe-N-C Electrocatalysts during Acidic Oxygen Reduction and Impact of Local pH Change

“…18,26,32 Nonetheless, flow cell ICP-MS studies are limited to low current densi�es, and cannot reproduce all the prac�cal condi�ons occurring in an opera�ng PEMFC device (O 2 par�al pressure and current density, lower rela�ve humidity). 33 In this respect, online gas diffusion electrode (GDE) ICP-MS is an adequate tool to simulate the environment of a PEMFC cathode more realis�cally, and gain PEMFCrelevant durability trends. For instance, Ehelebe et al first demonstrated significantly lower dissolu�on of Pt/C catalysts in GDE configura�on compared to flow cell systems due to varying mass transport condi�ons of Pt species, 34 as previously proposed.…”

Advancing the Rigor and Reproducibility of Electrocatalyst Stability Benchmarking and Intrinsic Material Degradation Analysis for Water Oxidation

“…Growing awareness of the limitations of amperostatic or potentiostatic stability metrics have led to the development of alternative, more catalyst-specific metrics to compare various catalyst candidates. 34 In 2017, Kim and co-workers proposed the activity−stability factor (ASF). 35 Similarly, in 2018 Geiger and co-workers introduced the S-number.…”