Synthesis and electrochemical performance of a LiMn1.83Co0.17O4 shell/LiMn2O4 core cathode material

A shell/core Co-incorporated LiMn2O4 cathode material was synthesized by a facile modified sol–gel process, using highly dispersed Mn3O4 nanoparticles as the Mn source. Structural characterization revealed that the shell layer, which was 5–10 nm thick, and composed of spinel LiMn1.83Co0.17O4, grew homogeneously on the spinel LiMn2O4 core with a size of ~50 nm. Electrochemical results showed that electrochemical performance of the shell/core cathode material compared favorably with that of the Co-doped LiMn2O4 counterparts. Also its rate capability and cycling performance were apparently superior to those of pristine LiMn2O4 synthesized under the same conditions. The shell/core cathode material exhibited a discharge capacity of 127 mAh g−1 at a current rate of 0.5 C (where 1 C=148 mA g−1), and retained a capacity of 103 mAh g−1 at 10 C, showing 81% capacity retention. After 200 cycles at 1 C and 25 °C, it delivered a capacity of 123 mAh g−1, retaining 98% of its initial capacity. After 100 cycles at 1 C and 55 °C, it showed a capacity of 118 mAh g−1, preserving 94% of its initial capacity. Its excellent electrochemical performance along with the facile synthesis process allowed the shell/core cathode material to serve as a promising cathode for high-performance Li-ion batteries.