An official website of the United States government
Understanding how particle size and morphology influence ion insertion dynamics is critical for a wide range of electrochemical applications including energy storage and electrochromic smart windows. One strategy to reveal such structure–property relationships is to perform ex situ transmission electron microscopy (TEM) of nanoparticles that have been cycled on TEM grid electrodes. One drawback of this approach is that images of some particles are correlated with the electrochemical response of the entire TEM grid electrode. The lack of one-to-one electrochemical-to-structural information complicates interpretation of genuine structure/property relationships. Developing high-throughput ex situ single particle-level analytical techniques that effectively link electrochemical behavior with structural properties could accelerate the discovery of critical structure-property relationships. Here, using Li-ion insertion in WO 3 nanorods as a model system, we demonstrate a correlated optically-detected electrochemistry and TEM technique that measures electrochemical behavior of via many particles simultaneously without having to make electrical contacts to single particles on the TEM grid. This correlated optical-TEM approach can link particle structure with electrochemical behavior at the single particle-level. Our measurements revealed significant electrochemical activity heterogeneity among particles. Single particle activity correlated with distinct local mechanical or electrical properties of the amorphous carbon film of the TEM grid, leading to active and inactive particles. The results are significant for correlated electrochemical/TEM imaging studies that aim to reveal structure-property relationships using single particle-level imaging and ensemble-level electrochemistry.
more »
« less
This content will become publicly available on December 1, 2026
Probing Interfacial Nanostructures of Electrochemical Energy Storage Systems by In-Situ Transmission Electron Microscopy
Abstract The ability to control the electrode interfaces in an electrochemical energy storage system is essential for achieving the desired electrochemical performance. However, achieving this ability requires an in-depth understanding of the detailed interfacial nanostructures of the electrode under electrochemical operating conditions. In-situ transmission electron microscopy (TEM) is one of the most powerful techniques for revealing electrochemical energy storage mechanisms with high spatiotemporal resolution and high sensitivity in complex electrochemical environments. These attributes play a unique role in understanding how ion transport inside electrode nanomaterials and across interfaces under the dynamic conditions within working batteries. This review aims to gain an in-depth insight into the latest developments of in-situ TEM imaging techniques for probing the interfacial nanostructures of electrochemical energy storage systems, including atomic-scale structural imaging, strain field imaging, electron holography, and integrated differential phase contrast imaging. Significant examples will be described to highlight the fundamental understanding of atomic-scale and nanoscale mechanisms from employing state-of-the-art imaging techniques to visualize structural evolution, ionic valence state changes, and strain mapping, ion transport dynamics. The review concludes by providing a perspective discussion of future directions of the development and application of in-situ TEM techniques in the field of electrochemical energy storage systems.
more »
« less
- Award ID(s):
- 2102482
- PAR ID:
- 10610660
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Nano-Micro Letters
- Volume:
- 17
- Issue:
- 1
- ISSN:
- 2311-6706
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Rechargeable batteries are crucial for energy storage across consumer electronics and automobile propulsion applications, facilitating the transition towards carbon neutrality and advancing clean energy technologies. Despite great success of Li-ion batteries (LIBs) in the commercial market, alternative technologies based on beyond-Li chemistry are highly demanded for large-scale and power-intensive applications necessitating enhanced energy density, lifetime, and safety, where fundamental understanding of the structure-property relationship of novel battery materials is critically needed. Transmission electron microscopy (TEM) is an indispensable method to characterize materials structures and compositions at the atomic scale, which is of particular importance for battery research to investigate crystal lattices, defects, as well as microstructural and chemical heterogeneities within materials used in electrodes, electrolytes, and their interfaces. Further, with rapid technical development, in-situ TEM has enabled real-time observations of various dynamical phenomena and chemical processes during battery cycling and phase transformations. Leveraging advanced in-situ TEM techniques, our collaborative endeavors with Dr. Marca Doeff have enabled us to conduct comparative analyses of Li and Na reactions within battery electrodes, offering unique insights into in early-stage beyond-Li chemistry. Herein, we present a systematic exploration of in-situ TEM studies for LIBs and beyond, focusing on electrode materials through intercalation, alloying, and conversion reaction mechanisms. By direct comparison between electrochemical reactions with Li and Na, we found substantial differences in reaction mechanisms, pathways, and kinetics between lithiation and sodiation processes, which are fundamentally related to various factors, such as ionic diffusion barrier, electrochemically induced stress, and geometric constraints. This concept has been demonstrated in multiple case studies that allows us to enhance the sodiation kinetics by tuning the overall reaction energetics through nanostructure optimization and interfacial engineering. We envision that the knowledge learned from in-situ TEM will provide valuable insights into understanding the alkali-ion electrochemistry and kinetics, thereby serving as foundational principles guiding the advancement of beyond Li-ion battery technologies.more » « less
-
Electrochemical energy systems such as batteries, water electrolyzers, and fuel cells are considered as promising and sustainable energy storage and conversion devices due to their high energy densities and zero or negative carbon dioxide emission. However, their widespread applications are hindered by many technical challenges, such as the low efficiency and poor long-term cyclability, which are mostly affected by the changes at the reactant/electrode/electrolyte interfaces. These interfacial processes involve ion/electron transfer, molecular/ion adsorption/desorption, and complex interface restructuring, which lead to irreversible modifications to the electrodes and the electrolyte. The understanding of these interfacial processes is thus crucial to provide strategies for solving those problems. In this review, we will discuss different interfacial processes at three representative interfaces, namely, solid–gas, solid–liquid, and solid–solid, in various electrochemical energy systems, and how they could influence the performance of electrochemical systems.more » « less
-
Developing a deeper understanding of dynamic chemical, electronic, and morphological changes at interfaces is key to solving practical issues in electrochemical energy storage systems (EESSs). To unravel this complexity, an assortment of tools with distinct capabilities and spatiotemporal resolutions have been used to creatively visualize interfacial processes as they occur. This review highlights how electrochemical scanning probe techniques (ESPTs) such as electrochemical atomic force microscopy, scanning electrochemical microscopy, scanning ion conductance microscopy, and scanning electrochemical cell microscopy are uniquely positioned to address these challenges in EESSs. We describe the operating principles of ESPTs, focusing on the inspection of interfacial structure and chemical processes involved in Li-ion batteries and beyond. We discuss current examples, performance limitations, and complementary ESPTs. Finally, we discuss prospects for imaging improvements and deep learning for automation. We foresee that ESPTs will play an enabling role in advancing EESSs as we transition to renewable energies.more » « less
-
Abstract Conversion‐type materials have been considered as potentially high‐energy‐density alternatives to commercially dominant intercalation‐based electrodes for rechargeable ion batteries and have attracted tremendous research effort to meet the performance for viable energy‐storage technologies. In situ transmission electron microscopy (TEM) has been extensively employed to provide mechanistic insights into understanding the behavior of battery materials. Noticeably, a great portion of previous in situ TEM studies has been focused on conversion‐type materials, but a dedicated review for this group of materials is missing in the literature. Herein, recent developments of in situ TEM techniques for investigation of dynamic phase transformation and associated structural, morphological, and chemical evolutions during conversion reactions with alkali ions in secondary batteries are comprehensively summarized. The materials of interest broadly cover metal oxides, chalcogenides, fluorides, phosphides, nitrides, and silicates with specific emphasis on spinel metal oxides and recently emerged 2D metal chalcogenides. Special focus is placed on the scientific findings that are uniquely obtained by in situ TEM to address fundamental questions and practical issues regarding phase transformation, structural evolution, electrochemical redox, reaction mechanism, kinetics, and degradation. Critical challenges and perspectives are discussed for advancing new knowledge that can bridge the gap between prototype materials and real‐world applications.more » « less
