Improved rate performance of LiNi0.5Mn1.5O4 cathode for lithium ion battery by carbon coating

Carbon-coated LiNi 0.5 Mn 1.5 O 4 cathode was prepared using phenolic resin as a carbon precursor. The morphology and structure of the prepared samples were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermogravimetry, and its performance as cathode of lithium ion battery was investigated by electrochemical impedance spectroscopy and charge-discharge test. The results showed that the carbon coating with phenolic resin as precursor could obviously promote the discharge capacity of LiNi 0.5 Mn 1.5 O 4 cathode, especially at high rate. At 20 C rate, the discharge capacity is 41 mAh∙g -1 for uncoated LiNi 0.5 Mn 1.5 O 4 , while 108 mAh∙g -1 for carbon-coated LiNi 0.5 Mn 1.5 O 4 . The coated sample also exhibited excellent cyclic performance, remaining 95 % of its initial discharge capacity (131 mAh∙g -1 ) at 1 C rate after 100 cycles. The interfacial resistance of LiNi 0.5 Mn 1.5 O 4 with carbon coating was reduced from 90 to 31 Ω.