We report the structural analysis on copper nitroprusside (CuNP) used as cathode material in a Li-ion battery during the first lithiation process. The investigation involved a multi-technique approach, where multiple edge Extended X-ray Absorption Fine Structure (EXAFS) refinement has been coupled with Density Functional Theory (DFT) calculations. The reduction occurring at the Cu site involves structural distortion, which is believed to be the main reason for the capacity fading in the first cycles.