Charging and Discharging Behavior of Solvothermal LiFePO4 Cathode Material Investigated by Combined EELS/NEXAFS Study

摘要

LiFePO4 cathode material obtained via solvothermal synthesis was investigated at several charging and discharging stages by a combination of bulk (EELS) and surface sensitive (NEXAFS) methods in order to get insight into the distribution of Li in the surface and bulk region of the particles. Different behavior was observed as a function of the particles morphology. The turbostratic stacking of layers in nanosized crystals induces higher dimensional defects responsible for sluggish Li insertion and extraction within the structure. In contrast, microstructured crystals without higher dimensional defects do not exhibit sluggish Li insertion/extraction, and achieve a higher degree of reversibility during electrochemical cycling.