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Abstract Discontinuous solid-solid phase transformations play a pivotal role in determining the properties of rechargeable battery electrodes. By leveraging operando Bragg Coherent Diffractive Imaging (BCDI), we investigate the discontinuous phase transformation in LixNi0.5Mn1.5O4within an operational Li metal coin cell. Throughout Li-intercalation, we directly observe the nucleation and growth of the Li-rich phase within the initially charged Li-poor phase in a 500 nm particle. Supported by the microelasticity model, the operando imaging unveils an evolution from a curved coherent to a planar semi-coherent interface driven by dislocation dynamics. Our data indicates negligible kinetic limitations from interface propagation impacting the transformation kinetics, even at a discharge rate of C/2 (80 mA/g). This study highlights BCDI’s capability to decode complex operando diffraction data, offering exciting opportunities to study nanoscale phase transformations with various stimuli.
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This content will become publicly available on September 1, 2026
Real‐Time Tracking of Nanoscale Morphology and Strain Evolution in Bi 2 WO 6 via Operando Coherent X‐Ray Imaging
Nanostructuring photocatalytic and catalytic materials substantially increases the surface‐to‐volume ratio, thereby exposing a greater number of active sites essential for enhanced catalytic efficiency. However, optimizing these efficiencies requires the non‐destructive,operandointerrogation of individual nanocrystals under realistic catalytic conditions—a capability that has long remained elusive. Here, this challenge is addressed by reporting three‐dimensional imaging of defects, crystal morphology, and strain dynamics in individual Bi2WO6(BWO) nanoflakes using Bragg coherent diffractive imaging (BCDI) underoperandotemperature, gas, and light‐driven conditions. It is demonstrated that maintaining a constant temperature of 40°C thermally activates charge carriers, likely enhancing their mobility and reducing recombination rates. Furthermore, an Argon (Ar) gas flow stabilizes the reaction environment, while a mixed Hydrogen–Nitrogen (H2+ N2) flow induces a hydrogen‐triggered semiconducting‐to‐metallic (SM) electronic phase transition accompanied by a structural transformation, as supported by density functional theory (DFT) calculations. Both DFT and BCDI analyses reveal that during the SM phase transition, a new structural phase nucleates near defects and propagates inhomogeneously. Notably, the onset of nanoscale cracking is observed, driven by localized strain accumulation and environmental cycling, which increases surface area and potentially introduces new reactive sites. These findings illustrate that combining advanced nanostructuring withoperandoimaging techniques can provide critical insights into the local structural features that govern photocatalytic performance, paving the way for the rational design of next‐generation photocatalytic materials.
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- Award ID(s):
- 2314614
- PAR ID:
- 10638462
- Publisher / Repository:
- Wiley-VCH GmbH
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 37
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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