The polyoxovanadate K7MnV13O38 (KMV) has been studied as cathode material of lithium ion batteries. The nanosize particles show initial discharge capacities over 308 and 225 mAh g(-1) at current densities of 17 and 167 mA g(-1) respectively. However, the capacity fading of nanosize particles is notably high with increasing cycle number, particularly when cycling at high rate. An effective approach to reduce the capacity fading is to use a composite cathode consisting of a mixture of nanosize particles and microsize particles in the weight ratio of 1:1. This composite cathode exhibits excellent cycle performance with capacity retention over 97% after 50 cycles at both low rate and high rate. (C) 2014 Elsevier B.V. All rights reserved.