Structural study of LiFePO4-LiNiPO4 solid solutions

► Ni-doped LiFePO4 olivines as cathodes for Li-ion batteries. ► Synthesis and electrochemical characterization show Li-ion improved performances. ► Rietveld X-ray structural refinement of solid solutions reveals anisotropic lattice contraction with Ni doping. ► Different size and geometrical distortions at the octahedral Fe/Ni sites are found by X-ray absorption (XANES, EXAFS) spectroscopy.