Composite of Li-rich Mn, Ni and Fe oxides as positive electrode materials for Li-ion battery

A porous layered composite of Li₂MnO₃ and LiMn_1/3Ni_1/3Fe_1/3O2 (composition: Li_1.2Mn_0.53Ni_0.13Fe_0.13O₂) is prepared by reverse microemulsion method employing tri-block co-polymer, F068 as a soft-polymer template. The Co-free composite is studied as a cathode material for Li-ion battery. Several samples are prepared by heating the precursor in the temperature range between 500 and 900°C. The N₂ adsorption/desorption studies reveal that the product samples possess mesoporosity with broadly distributed pores around 15-50 nm diameter. Pore volume and surface area decrease by increasing the temperature of preparation. Charge-discharge, cycling and rate capability are investigated. The discharge capacity of the sample prepared at 900°C is about 170 mAh g^-1 at a specific current of 25 mA g^-1 with a good cycling stability. A value of 140 mAh g^-1 is obtained at the end of 50 charge-discharge cycles. Discharge capacity of 91 mAh g^-1 is obtained at a specific current of 206 mA g^-1. A high rate capacity of the composite is attributed to its porous nature.