Na-0.6[Li0.2Mn0.8]O-2 has been synthesized at different calcination temperatures by a solid state method. Its phase structure and electrochemical properties are investigated and discussed. Na-0.6[Li0.2Mn0.8]O-2 prepared at 600 degrees C shows a complicated structure and wonderful electrochemical performance. In the voltage range of 2.0 and 4.8 V. Na-0.6[Li0.2Mn0.8]O-2/Li cell delivers an initial discharge capacity of 247 mAh g(-1) with an average voltage of 3.52 V, which demonstrates a very high energy density of 869 Wh kg(-1). Furthermore, the material displays a stable capacity greater than 240 mAh g(-1) over 30 cycles. (C) 2013 Elsevier B.V. All rights reserved.