Commercial MoS 2 was lithiated by soaking in butyllithium in argon atmosphere. The lithiated samples (LixMoS 2) exhibited greatly improved electrochemical performance. Li xMoS 2 showed a high reversible capacity of 669.5 mAh g -1 and excellent cycling stability, with an average capacity loss of merely 0.065% per cycle. The rate capability of the Li xMoS 2 electrode was also improved compared to that of the unlithiated MoS 2 electrode. The x-ray diffraction and high resolution transmission electron microscopy (TEM) results prove that there was an increase in the c lattice parameter for the lithiated material. The magnetic properties and evaluations of conductivity in MoS 2 and Li xMoS 2 show that the electric conductivity of Li xMoS 2 is much higher than that of MoS 2. TEM images after 11 cycles demonstrated that the Li xMoS 2 electrode consisted of more uniform small particles, while big particle blocks could be observed for the MoS 2 electrode. All of these might be favourable for the electrochemical performance. © 2012 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA,Weinheim.