To elucidate the Li+ extraction and insertion mechanism for Li2FeSiO4 nanoparticles, at the atomic scale, X-ray absorption spectroscopy (XAS) measurements at Fe and Si K-edges were performed. Fe K-edge XAS spectra suggest irreversible changes occurring in the local and electronic environment of iron which can be attributable to the characteristic shift in potential plateau during initial cycling of Li2 - xFeSiO4 system. While the local environment around Fe atoms significantly changes upon initial cycling, the local Si-O environment is mostly maintained. (C) 2013 Elsevier B.V. All rights reserved.