The nanocomposite granule of LiMnPO4 nanoparticles and carbon were directly and rapidly created from the starting powder materials by one-step mechanical method without extra heat assistance. The primary particle size and the granule particle size obtained by this method were less than 20 nm and around 20 mu m, respectively. The granules could be compacted easily to be the electrode for high packing density. The cathode electrode made by the granules also consisted of the network structure of LiMnPO4 and that of carbon, thus reduced the lithium ion diffusion path and achieved high electron conductivity. Although, the specific capacity was still 60% of the theoretical capacity, it is expected to be innovative energy-saving process for manufacturing lithium ion batteries by better control of the granule structure in future. (C) 2013 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.