Fig. 4

Structure conversion of Fe0.9Co0.1OF nanorod monitored in real time and the elemental composition distribution. a Schematic illustration of the electrochemical setup for in situ TEM test. b In situ HRTEM image of Fe0.9Co0.1OF during dynamic lithiation at 1.2 V for different time. c The lithiation distance and the volume change as function of time. d ADF-STEM image and e corresponding Fe, Co, O, and F elemental distributions after the first lithiation obtained by STEM-EELS technique. Scale bar in b and d is 20 and 10 nm, respectively