Advanced analytical electron microscopy for lithium-ion batteries

Lithium-ion batteries are a leading candidate for electric vehicle and smart grid applications. However, further optimizations of the energy/power density, coulombic efficiency and cycle life are still needed, and this requires a thorough understanding of the dynamic evolution of each component and their synergistic behaviors during battery operation. With the capability of resolving the structure and chemistry at an atomic resolution, advanced analytical transmission electron microscopy (AEM) is an ideal technique for this task. The present review paper focuses on recent contributions of this important technique to the fundamental understanding of the electrochemical processes of battery materials. A detailed review of both static (ex situ) and real-time (in situ) studies will be given, and issues that still need to be addressed will be discussed. Recent advances in advanced analytical electron microscopy (AEM) and their implications for studying lithium-ion batteries are reviewed. Lithium-ion batteries are promising for powering electric vehicles and for use in smart grid applications, but require further optimization before they can achieve widespread use in these applications. Powerful advanced AEM techniques are ideal for gaining unprecedented insight into the dynamic processes of active lithium-ion batteries. Miaofang Chi, a research scientist at Oak Ridge National Laboratory, and her co-workers overview recent developments in novel AEM capabilities and demonstrate how such methods have created unrivaled opportunities for understanding the working mechanisms of battery materials. Both static, ex situ studies and newly developed in situ AEM techniques, which offer the opportunity to explore dynamic electrochemical processes during charging and discharging, are highlighted. The scientists also propose future directions. This review highlights the recent developments and contributions of advanced electron microscopy studies to the research of lithium-ion battery materials. Both static, ex situ studies and newly developed in situ AEM techniques are emphasized, and future directions are also proposed.