Application of Advanced Characterization Techniques for Lithium Iron Phosphate: Paving the Way for an In-Depth Understanding of Operation and Fading Mechanisms

The exploitation and application of advanced characterization techniques play a significant role in understanding the operation and fading mechanisms as well as the development of high-performance energy storage devices. Taking lithium iron phosphate (LFP) as an example, the advancement of sophisticated characterization techniques, particularly operando / in situ ones, has led to a clearer understanding of the underlying reaction mechanisms of LFP, driving continuous improvements in its performance. This Review provides a systematic summary of recent progress in studying LFP by using a wide range of advanced characterization techniques. Based on the principles and functions, two types of characterization techniques, bulk and surface/interface studies, and the corresponding application in understanding the bulk phase transition and the surface/interface reaction mechanisms of LFP are introduced. Additionally, the limitations of current research methods, the controversial viewpoints, as well as the suggestions for the future research directions are also addressed for inspiring further developments in related systems.