Abstract High energy density composite cathode, 0.3Li2MnO3–0.7LiNi0.5Mn0.5O2 was prepared using two different wet chemical routes viz. co-precipitation and sol–gel methods. The powder X-ray diffraction patterns and Raman spectra of the samples showed clear evidence of the composite nature. Microscopy analysis revealed the particle sizes of the materials prepared by co-precipitation and sol–gel methods are 1.5–2.0µm and 350–550nm, respectively. Charge–discharge tests indicate the better electrochemical performance of the sol–gel prepared composite in terms of high discharge capacity (∼240mAh/g) and good cycling performance. The improved electrochemical performance was attributed to a decrease in the charge-transfer resistance and high surface area.