In this study, we report the preparation and electrochemical evaluation of LiFePO4-carbon nanocomposites with carbon aerogels of varied pore size and distribution. In these composites, LiFePO4 nanoparticles smaller than 50 nm are confined to a three-dimensional (3D) microporous network that functions as the electronic and ionic conductor. The pore size of carbon aerogel is adjusted to achieve smaller LiFePO4 nanoparticles. The KOH activation treatment of carbon aerogels is used to increase micropores that act as electrolyte reservoirs and is beneficial for ionic conductivity. Additional carbon coating of LiFePO4 particles using glucose further enhances the electrode performance. The resultant composite electrodes exhibit superior rate performance and good cyclic stability due to the optimized nanostructure. The nanocomposites of LiFePO4 and carbon areogels provide good examples of material nano-engineering owing to their tunable nanostructures. (C) 2013 Elsevier B.V. All rights reserved.