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

Abstract A shell/core Co-incorporated LiMn 2 O 4 cathode material was synthesized by a facile modified sol–gel process, using highly dispersed Mn 3 O 4 nanoparticles as the Mn source. Structural characterization revealed that the shell layer, which was 5–10 nm thick, and composed of spinel LiMn 1.83 Co 0.17 O 4 , grew homogeneously on the spinel LiMn 2 O 4 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 LiMn 2 O 4 counterparts. Also its rate capability and cycling performance were apparently superior to those of pristine LiMn 2 O 4 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.