Samples of Li2FeSiO4 and Li2Fe1-xNixSiO4/C (x = 0, 0.05, 0.10, 0.15, 0.20 and 0.30) were prepared via a solid state reaction assisted by mechanical milling and characterized by X-ray diffraction and transmission Mössbauer spectroscopy. Sucrose was used as carbon sources. Rietveld analysis of the X-ray difratograms and Mossbauer results indicate that the orthosilicates crystallize in as a monoclinic P21/n phase with uniform crystallite sizes. The pristine phase Li2FeSiO4 is paramagnetic. It is noted that nickel doped lithium iron orthosilicates, Li2Fe1-xNixSiO4, in the experimental conditions used, undergo carbothermal reduction. Carbon promotes a highly reductive environment for the formation of such phases Fe1-xNix impairing optimal formation of a composite of carbon coated orthosilicate.
