The Li-1.20[Mn0.52-xGdxNi0.20Co0.08]O-2 (x = 0, 0.01,0.02, 0.03) cathode materials have been synthesized by using the combination of co-precipitation with high temperature sintering method. The XRD, SEM, TEM and galvanostatic charge-discharge tests were carried out to study the influence of Gd3+ doping on the crystal structural, morphology and electrochemical properties of Li-1.20[Mn0.52Ni0.20Ni0.08]O-2. The XRD result revealed the Gd3+ doping modification could decrease the cation mixing degree. The galvanostatic charge-discharge tests results showed the improved electrochemical properties were obtained through the Gd3+ doping modification. With the increase of Gd3+ doping content, the capacity retentions enhanced from 88.1% to 903% and then decrease to 87.0% after 100 cycles with x = 0.01,0.02 and 0.03, respectively, while the un-doped sample delivered the capacity retention of 85.1%. The Li-1.20[Mn0.50Gd0.02Ni0.20Co0.08]O-2 exhibited a discharge capacity of 115.5 mAh g(-1) at 5C rate, much larger than that (85.1 mAh g(-1)) of the un-doped Li-1.20[Mn0.52Ni0.20Co0.08]O-2. The cyclic voltammetric analysis has proved that the Gd3+ doping modification can keep the stability of the cathode layer structure and further hold the high working voltage. (C) 2018 Published by Elsevier B.V.