Fei Wang, Yanshan University, Advanced Materials: The study of structure-activity relationship at the single particle scale provides a new idea for the development of high-performance batteries
【Article Information】
The study of structure-activity relationship at the single particle scale provides a new idea for the development of high-performance batteries
First Author: Wang Fei
Contact: WANG Fei*, WU Fan*, HUANG Yudong*
Affiliation: Yanshan University, North University of China, Harbin Institute of Technology
【Background】
With the increasing requirements for battery energy density and power density in electric vehicles, portable electronic devices and tools, continuously improving battery performance is the focus of research. Accurate measurement of the structure-effectiveness relationship of active materials is key to advancing high-performance battery research. However, traditional active material performance testing is based on electrochemical measurements of porous composite electrodes containing active materials, polymer binders, and conductive carbon additives, which does not establish an accurate structure-activity relationship with the physical characterization of microregions. In order to facilitate the accurate measurement and understanding of the structure-activity relationship of materials, the electrochemical measurement and physical characterization of energy storage materials at the single particle scale are reviewed. The potential problems and possible improvement schemes in the electrochemical measurement and physical characterization of single particles are proposed. Their potential applications in single-particle electrochemical simulation and machine learning are prospected. The aim of this paper aims to further promote the application of electrochemical measurement and physical characterization of single particles in energy storage materials, and hopes to realize the three-dimensional unified evaluation of electrochemical measurement, physical characterization and theoretical simulation at the single particle scale, so as to provide new inspiration for the development of high-performance batteries.
【Introduction】
近日，燕山大学王飞等，在国际知名期刊Advanced Materials上发表题为“Investigation of the Single-Particle Scale Structure–Activity Relationship Providing New Insights for the Development of High-Performance Batteries”的观点文章。 该观点文章综述了储能材料在单颗粒尺度上的电化学测量和物理表征，同时展望了它们在单颗粒电化学模拟和机器学习中的潜在应用前景。
Figure 1. Schematic diagram of the topic structure of the review.
【Main points of the text】
Point 1: Electrochemical measurement of single particles of energy storage materials
The traditional way to study the performance of energy storage materials is to measure the performance of porous composite electrodes containing active materials, polymer binders, and conductive carbon additives. The binder, conductive agent and electrode structure of the composite electrode have a significant impact on the electrochemical test results, which is not conducive to revealing the inherent electrochemical kinetics and properties of energy storage materials.
Electrochemical measurements of composite electrodes generally assume that ion transport in the electrolyte and transport of electrons to the active center are not rate-controlled steps. However, when studying the fast charge-discharge properties of energy storage materials, electrons must reach the active center through many solid-solid interfaces, and ions in the electrolyte must travel long distances to reach the surface of the active material. The transport of ions and electrons in the composite electrode may become a rate-controlled step in the fast charge-discharge performance, which will affect the accurate measurement of the fast charge-discharge performance of the active material. The electrochemical measurement of the composite electrode can be seen as a compromise between a simple experimental setup and the accuracy of certain kinetic parameters, such as the exchange current density and diffusion coefficient. Single-particle electrochemical measurements of energy storage materials can measure the intrinsic electrochemical information of active materials more accurately than composite electrodes. Through the electrochemical measurement and physical characterization of single particles, the accurate structure-activity relationship of energy storage materials can be established. At present, the reported single-particle electrochemical measurement techniques for energy storage materials mainly include microelectrode-based single-particle electrochemical measurement and scanning electrochemical cell microscopy (SECCM).
Fig.2 Electrochemical measurement of single particles of energy storage materials based on microelectrodes
Fig.3 Electrochemical measurement of single particles of energy storage materials based on microelectrodes
Fig.3 Single-particle electrochemical measurement based on scanning electrochemical cell microscopy (SECCM) and its coupling with in-situ physical characterization
Fig.4 Electrochemical measurements based on scanning ion conductance microscopy, electrochemical strain microscopy, scanning electrochemical microscopy, and nanocollisions
Point 2: Physical characterization of single particles of energy storage materials
Real-time tracking and understanding of the dynamic processes of functional materials at the nano- or microscale, in situ or under operating conditions, can help advance the development of advanced lithium-ion battery materials and technologies, especially fast charging technologies for batteries. Optical Interference Scattering Microscopy (ISCAT) and Surface Plasmon Resonance Microscopy (SPRM) are fast, high-throughput, and low-cost imaging platforms that enable rapid, high-sensitivity, and high-throughput signal acquisition to visualize and quantify ion dynamics at the single-particle scale.
Fig.5 In-situ characterization based on optical interference scattering microscopy (ISCAT) and surface plasmon resonance microscopy (SPRM).
The rapid development of in-situ transmission electron microscopy (TEM) technologies such as low acceleration voltage, environmental chamber, and liquid battery holder can well reveal the physical and chemical parameters of the reaction process of energy storage materials, and can have significant advantages in monitoring the composition and structural evolution, phase transition, and dynamic interface behavior of active materials at atomic resolution. At the same time, X-ray microscopy characterization techniques excel in providing information on the structural composition and morphology of materials.
Fig.5 In-situ characterization based on in-situ TEM
Fig.6 In-situ characterization based on X-ray microscopy
Point 3: Outlook and conclusions
The electrochemical measurement of a single particle combined with the in-situ or in-situ physical characterization of a single particle can accurately reflect the structure-activity relationship of the active material at the level of a single particle, providing a new perspective for the rational design and optimization of high-performance batteries. To better understand the complex processes that occur inside batteries, researchers are relying not only on experiments, but increasingly on model simulations. Theoretical simulations are widely used to simulate the physical and electrochemical processes that occur inside lithium-ion batteries, providing insight into complex processes such as electrochemical reactions, ion diffusion, volume changes, stress changes, heat production, and conduction inside the battery. Reasonable simulation is helpful to solve the core problems in battery research, such as: 1. Capacity attenuation and cycle life prediction of batteries; ii: Real-time evaluation of the battery's SOC and state of health (SOH); iii.: Optimal design of active materials, electrode structures, and electrolytes; Theoretical models face several challenges in lithium-ion battery research, for example, the accuracy of the model is largely dependent on the accuracy of the input parameters. These parameters are often determined experimentally with the potential for error.
Unifying electrochemical measurements and physical characterization at the single-particle scale can provide accurate electrochemical and corresponding physical structure parameters for theoretical simulation of batteries. For example, the electrochemical measurement of single particles shows that there are great differences between single particle energy storage materials and composite electrodes in terms of rate and cycling performance. This shows that there is still a lot of room for further optimization of the battery and electrodes to improve the performance of the battery. Single-particle scale electrochemical measurements and physical characterization can provide accurate active material structure-activity parameters for the accurate construction of multi-scale and multi-physics battery models, which is expected to bring more breakthroughs and innovations to future energy storage technologies. In particular, a highly unified three-dimensional evaluation of the physical properties, electrochemical measurements, and theoretical simulations of materials at the single-particle level is essential to understand the core issues such as the energy storage mechanism, decay mechanism, and active material-electrolyte interface of various energy storage materials.
In the context of the rapid development of artificial intelligence and machine learning technology, obtaining accurate electrochemical information and the corresponding physical composition and structure information of energy storage materials is particularly critical for the application of artificial intelligence in the battery field. Accurate information is not only the key to building accurate battery electrochemistry models, but also an important foundation for machine learning model training and optimization. In the foreseeable future, the application of artificial intelligence (AI) will greatly accelerate the development of high-performance batteries.
Figure 7: A schematic diagram of single-particle level electrochemical measurements and physical characterization that provide accurate underlying data information to facilitate the application of artificial intelligence in battery research.
In recent years, significant progress has been made in electrochemical measurement and physical characterization techniques at the single particle scale, which provides strong support for understanding the energy storage mechanism, decay mechanism, and active material-electrolyte interface of energy storage materials. In this paper, the electrochemical measurement and physical characterization of energy storage materials at the single particle scale are reviewed, aiming to promote the further application of accurate structure-activity relationship measurement and characterization in the development of high-performance batteries. Although single-particle electrochemical measurement is playing an increasingly important role in revealing the intrinsic properties of energy storage materials, the challenge is how to organically combine single-particle electrochemical measurement with single-particle in-situ physical characterization techniques to gain a more comprehensive and in-depth understanding of the behavior and mechanism of active materials in electrochemical processes. It is of great significance to develop a simple single-particle electrochemical measurement method with high signal-to-noise ratio to realize the unification of single-particle scale electrochemical measurement and physical characterization.
At present, the application of single particle electrochemical testing combined with in-situ transmission and spectrophysical characterization does show great feasibility. In the context of the rapid development of artificial intelligence and computing power, electrochemical measurements and physical characterization at the single particle scale are playing an increasingly important role in accurately revealing the structure-activity relationship of active species. This accurate understanding of the structure-activity relationship is of great value for single-particle simulations and large-scale battery models, helping to further optimize battery performance and design innovation.
【Article Link】
“Investigation of the Single-Particle Scale Structure–Activity Relationship Providing New Insights for the Development of High-Performance Batteries”
https://doi.org/10.1002/adma.202400683
【About the Corresponding Author】
Fei Wang's profile: Fei Wang received his master's degree in chemical engineering from Harbin Institute of Technology in 2017 and his Ph.D. in chemical engineering and technology from Harbin Institute of Technology in 2021. After graduation, he went to Changchun Institute of Applied Chemistry, Chinese Academy of Sciences for postdoctoral research. In 2023, he joined Yanshan University, focusing on the research of electrochemical energy storage materials and polymer electrolytes in advanced battery chemistry. As the first author and corresponding author, he has published many research papers in academic journals such as Advanced Materials, ACS nano, Cell Reports Physical Science, Chemical Engineering Journal, Nano Research, Rare Metals, etc.
Wu Fan received his B.S. in Materials Chemistry from Harbin Institute of Technology in 2017 and Ph.D. in Chemical Engineering and Technology from Harbin Institute of Technology in 2023. After graduation, she joined North University of China, focusing on the research of advanced battery chemistry polymers.
Huang Yudong Profile: Huang Yudong has worked in Harbin Institute of Technology for more than 30 years and won the second prize of the National Technological Invention Award twice. The research focuses on key technologies and engineering research in polymer reaction engineering and interfacial chemical engineering.