In order to develop a better understanding of Li-doping in SnO2 nanoparticles, a gel-sol method of synthesis is employed to systematically examine the influence of reaction and growth conditions such as pH, dopant concentration, and calcinations temperature. The extent of Li doping in nanoparticles is characterized using nuclear reaction analysis (NRA) and the nanostructure with high-resolution electron transmission microscopy (HR-TEM) and X-ray diffraction (XRD) techniques. The NRA reports that the lithium incorporation only takes place at alkaline pH (> 8). The XRD and TEM results indicate that the crystallite size exhibits a maximum at a pH of 8 increasing (decreasing) with calcinations temperature (dopant concentration), while preserving the casserite crystal structure (tetragonal rutile) under these reaction conditions. A preliminary analysis suggests a nanoscopic phase separation of lithium poor crystalline core and lithium rich amorphous shell may occur with increased dopant concentration. (c) 2006 Elsevier B.V. All rights reserved.