Orthorhombic LiMnO 2 was synthesized via the sol–gel process using citric acid as a chelating agent. The effect of varying the molar acid to metal ions ratio ( R) on the structural and electrochemical properties of the synthesized compound was studied. Samples with high R ( R=1,2) contain large amount of MnO impurity phase, which is electrochemically inactive and thus is detrimental to the electrochemical activity of the electrode. Therefore, the acid to metal ions ratio “ R” should not be high. Samples with low R ( R=0.5) exhibited a high initial capacity, above 190 mAh/g when cycled at a current density of 0.4 mA/cm 2 at room temperature. The ac impedance results show that the initial capacity was improved (compared with ss- o-LiMnO 2) due to the smaller particle size and good homogeneity, which improves the Li + diffusion in the cathode.