Proton‐Mediated and Ir‐Catalyzed Iron/Iron‐Oxide Redox Kinetics for Enhanced Rechargeability and Durability of Solid Oxide Iron–Air Battery

Abstract

Long duration energy storage (LDES) is an economically attractive approach to accelerating clean renewable energy deployment. The newly emerged solid oxide iron-air battery (SOIAB) is intrinsically suited for LDES applications due to its excellent low-rate performance (high-capacity with high efficiency) and use of low-cost and sustainable materials. However, rechargeability and durability of SOIAB are critically limited by the slow kinetics in iron/iron-oxide redox couples. Here the use of combined proton-conducting BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3 (BZC4YYb) and reduction-promoting catalyst Ir to address the kinetic issues, is reported. It is shown that, benefiting from the facilitated H + diffusion and boosted FeO x -reduction kinetics, the battery operated under 550 °C, 50% Fe-utilization and 0.2 C, exhibits a discharge specific energy density of 601.9 Wh kg -1 -Fe with a round-trip efficiency (RTE) of 82.9% for 250 h of a cycle duration of 2.5 h. Under 500 °C, 50% Fe-utilization and 0.2 C, the same battery exhibits 520 Wh kg -1 -Fe discharge energy density with an RTE of 61.8% for 500 h. This level of energy storage performance promises that SOIAB is a strong candidate for LDES applications.

A Kinetic Study on H2 Reduction of Fe3O4 for Long-Duration Energy-Storage-Compatible Solid Oxide Iron Air Batteries

“…The ability of BZCYYb to retain water thus proton has been previously postulated as the mechanism for the boosted reduction kinetics. 18 The morphologies of Fe 3 O 4 /BZC4YYb/Ir before and after reduction are shown in Fig. 14 of SEM image.…”

“…In addition, we have also demonstrated the benefits of replacing ZrO 2 with a proton containing perovskite BaZr-0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3 (BZC4YYb). 17,18 However, there is a lack of reduction kinetics datasets for Ir-catalyzed FeO x -ZrO 2 and FeO x -BZCYYb systems. Therefore, the goal of this study is to acquire this set of kinetic data for comparison with the baseline FeO x -ZrO 2 and future Multiphysics modeling of the battery.…”

All-Solid-State Iron-Air Batteries: A Promising High-Temperature Battery Technology for Large-Scale Energy Storage

“…The SOIARB presents numerous advantages due to its solidoxide structure, which guarantees safety, modularity, compactness, and scalability. [13][14][15][16][17][18][19] Fang et al validated the concept of Fe-air batteries using Fe/FeO x redox couples in planar short stacks based on conventional solid oxide fuel cells and electrolysis technology. 20 A novel method employing an H 2 bypass and capillary tube allowed the SOC test bench to be used to build and test Fe-air batteries without complicated modifications.…”