Single particles electrochemistry for batteries

Ion migration is the most fundamental process in the field of energy storage and conversion. During the charge discharge cycle, the (de)intercalation of guest ions in solid host particles as electrode materials change the distribution of element, phase and stress in the particle and give rise to crushing and degradation, which will influence the electrochemical behavior of the particles. New methods are constantly being proposed to probe the electrochemical reactions on individual particle for understanding the mechanism of the process. In this short review, we highlight some pioneer works from two different perspectives, namely direct electrochemical detection methods, such as nano-impact method, nanoprobe detection and flowing particle analysis, and indirect optical analysis methods utilizing X-ray imaging, infrared near-field nanoscopy, Raman microscopy and surface plasmon resonance microscopy.