Nanorod structures of LiMn1.8Ni0.2O4 applicable as active cathode material for Li-ion batteries were synthesized from alpha-MnOOH and alpha-MnO2 initial phases. The LiMn1.8Ni0.2O4 spinel nanorods obtained from a-MnOOH using a novel, eco-friendly method showed higher purity than the traditional spinel obtained from alpha-MnO2. The showed charge capacity that was in the order of 122 mA h g(-1) higher than similar active material reported in the literature, and it was able to keep > 80% of initial capacity at a charge rate of 5 C.