In the present work, we have reported the electrochemical performance of xLi(2)MnO(3)-(1-x)Li(Mn0.375Ni0.375Co0.25)O-2 (0.0 <= x <= 1.0) integrated cathodes for high energy density lithium rechargeable batteries. For x = 0.5 cathode we have reported discharge capacity of 290 mAhg(-1) with capacity retention similar to 76% after 50 cycles at 10 mAg(-1). It is remarkable to find x = 0.75 to yield discharge capacity similar to 235 mAhg(-1) and excellent capacity retention up to 50 cycles. Our work will pave way to explore Li2MnO3 rich (x >= 0.5) integrated cathodes to economic environmentally benign manganese rich, high voltage, high capacity lithium ion batteries. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.081207jes] All rights reserved.