A Li2MnSiO4 cathode material for lithium-ion batteries was prepared by a molten carbonate flux method. The preparation conditions such as gas atmospheres, heating temperatures and manganese sources were examined. Single phase Li2MnSiO4 was obtained at 500 degrees C with two kinds of manganese sources (manganese oxalate dihydrate and manganese hydroxide), which was confirmed using high-resolution synchrotron X-ray diffraction (XRD). The Li2MnSiO4 prepared using manganese hydroxide has smaller particle size (100-300 nm) and higher specific surface areas (19.4 m(2) g(-1)) than those prepared using manganese oxalate dihydrate (200-600 nm, 12.5 m(2) g(-1)). Former sample showed higher discharge capacity (156 mAh g(-1)), initial efficiency (89%) and capacity retention (55% on 20th cycle) than latter one (92 mAh g(-1), 69% and 37% on 20th cycle). (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.jes113317] All rights reserved.