Electrochemical performances of Li-rich layered-layered Li2MnO3-LiMnO2 solid solutions as cathode material for lithium-ion batteries

In this work a series of Li-rich layered-layered solid solution of Li2MnO3-LiMnO2 [Li[Li(1−x)/3Mn(x+2)/3]O2; x = 0.0, 0.1, 0.3 and 0.5] nanocomposite structure were successfully synthesized using sol-gel technique. All the synthesized compositions exhibit the main characteristics peaks of m-Li2MnO3 and could be indexed to the C2/m space group except some weak diffraction peaks located around 20-30° which can be attributed to the superlattice structure originate due to the ordering of Mn ion into Li-Mn layers and are typically observed for Li-rich based materials. CV results show that pristine LMO possesses weak anodic peak around 4.7 V and no symmetric cathodic peak in the voltage window of 2.0-4.8 V. Among all the synthesized compositions, x = 0.3 (LMO3) delivers highest specific discharge capacity and best rate and cycling performances at all values of current densities. The LMO3 composition delivers an initial discharge capacity of 177 ± 5 mAhg−1 at a current density of 10 mA/g in the voltage range of 2.0-4.8 V and holds nearly 97% of the initial discharge capacity after 120 charge/discharge cycles at the same current density.