In the present study, we performed a new ex situ analysis of the change in the crystal structure of a cathode containing the composite material in a coin cell during the charge discharge cycle. Time-of-flight neutron powder diffraction with Rietveld refinement was used to analyze the crystal structure of LiNi0.8Co0.19Cu0.01O2 produced by solid-phase synthesis, both for the powder and a cathode before and after charging. The powder and the cathode had similar crystal structure parameters before charging. The results obtained demonstrate that crystal structure analysis by neutron diffraction is possible for a cathode containing 8.5 mg of active material. The results also showed that it is possible to quantitatively determine the Li composition, Li/Ni cation mixing amount, (Ni,Co,Cu)-O-6 octahedral distortion, and small quantities of the second phase component in the cathode before and after charging.