Electrochemical performance behavior of combustion-synthesized LiNi0.5Mn0.5O2 lithium-intercalation cathodes

LiNiO2, partially substituted with manganese in the form of a LiNi0.5Mn0.5O2 compound, has been synthesized by a gelatin assisted combustion method [GAC] method. Highly crystalline LiNi0.5Mn0.5O2 powders with R3m symmetry have been obtained at an optimum temperature of 850 °C, as confirmed by PXRD studies. The presence of cathodic and anodic CV peaks exhibited by the LiNi0.5Mn0.5O2 cathode at 4.4 and 4.3 V revealed the existence of Ni and Mn in their 2+ and 4+ oxidation states, respectively. The synthesized LiNi0.5Mn0.5O2 cathode has been subjected to systematic electrochemical performance evaluation, via capacity tapping at different cut-off voltage limits (3.0–4.2, 3.0–4.4 and 3.0–4.6 V) and the possible extraction of deliverable capacity under different current drains (0.1C, 0.5C, 0.75C and 1C rates). The LiNi0.5Mn0.5O2 cathode exhibited a maximum discharge capacity of 174 mAh g−1 at the 0.1C rate between 3.0 and 4.6 V. However, a slightly decreased capacity of 138 mAh g−1 has been obtained in the 3.0–4.4 V range, when discharged at the 1C rate. On the other hand, extended cycling at the 0.1C rate encountered an acceptable capacity fade in the 3.0–4.4 V range (<10%) for up to 50 cycles.