Microstructure dynamics of rechargeable battery materials studied by advanced transmission electron microscopy

The ever-growing energy requirements, the decreasing fossil fuel resources and the urgent need for environmental protection have spurred the search for sustainable energy alternatives, including both renewable energy sources and efficient storage technologies. Lithium/sodium (Li/Na)-ion batteries (LIBs/SIBs) are the most attractive and promising energy storage devices in the consumer market. The primary progress made by using advanced transmission electron microscopy (TEM) characterization and its close correlation with the battery properties are reviewed here. In addition, the atomic structure and chemistry of electrode materials are illustrated with respect to the surface reconstruction and the interface structure. The phase transformation and defect evolution are then discussed with respect to (1) the intermediate state of LiFePO4 that results in a high rate capability; (2) the in situ electrochemical reaction on nanomaterials; and (3) the alloying reaction for the high-energy-density silicon (Si) anode. The fundamental science underlying the microstructure evolution has been explored in depth to the atomic level and is discussed further in the context of electronic structure theory.