We have developed and tested cell for laboratory operando diagnostics of Li-ion cathode materials. Local atomic and electronic structure of LiFe1-xMnxPO4 olivine cathode was studied by means of Fe and Mn K-edges XAS and Mössbauer spectroscopy. Analysis of XAS data allows us to follow the structural and oxidation state changes occurring during the cell cycling. Together with operando Mössbauer spectroscopy sensitive to the fine Fe ions local coordination distortions escaping from laboratory XANES, we are able to prove the homogeneity of Fe and Mn ions distribution.