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DOE OSTI · 2998143

Electronic Structure and Safety Insights into Prussian Blue Analog Cathode Behavior at Elevated Temperatures in Sodium-Ion Batteries

Shipitsyn, Vadim [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)] (ORCID:0009000865210216)·Zuo, Wenhua [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000319772775)·Tran, Thanh-Nhan [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:000000020121062X)·Li, Tianyi [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000262346096)·Lee, Sungsik [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000214259852)·Chak, Chanmonirath Michael [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)]·Le, Phung M. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000310553672)·Ma, Lin [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)] (ORCID:0000000311831347)
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Abstract

Prussian blue analogs (PBAs) represent promising cathode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity, open framework structure, and use of earth-abundant elements. However, the high-temperature structural evolution, water content effects, and thermal safety of PBAs, particularly in charged states, remain poorly understood, hindering their practical deployment. Here, we investigate Na 2 Fe[Fe(CN) 6 ]·2H 2 O using thermogravimetric analysis (TGA), ex situ and in situ temperature-dependent X-ray absorption spectroscopy (XAS), and accelerated rate calorimetry (ARC). TGA and ex situ XAS confirm water loss between 150 and 200 °C, resulting in Fe 2+ oxidation, enhanced local symmetry, and uniform redox behavior that improves electrochemical performance. In situ XAS reveals irreversible structural changes above 240 °C, including ligand loss, Fe site distortion, and increased disorder, while ARC on charged electrodes shows minimal self-heating rates (<0.1 °C/min) up to 300 °C, indicating exceptional thermal stability without lattice oxygen release. These insights elucidate PBA thermal dynamics, demonstrating improved electrochemical performance of water-deficient PBAs and informing future material design and safety assessment for SIB applications.

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Shipitsyn, Vadim [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)] (ORCID:0009000865210216), Zuo, Wenhua [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000319772775), Tran, Thanh-Nhan [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:000000020121062X), Li, Tianyi [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000262346096), Lee, Sungsik [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000214259852), Chak, Chanmonirath Michael [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)], Le, Phung M. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000310553672), Ma, Lin [University of North Carolina, Charlotte, NC (United States); University of North Carolina, Chapel Hill, NC (United States)] (ORCID:0000000311831347). 2025-09-22. Electronic Structure and Safety Insights into Prussian Blue Analog Cathode Behavior at Elevated Temperatures in Sodium-Ion Batteries. https://doi.org/10.1021/acs.energyfuels.5c03083

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