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

摘要

Carbon-coated LiNi0.5Mn1.5O4 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 LiNi0.5Mn1.5O4 cathode, especially at high rate. At 20 C rate, the discharge capacity is 41 mAha (TM) g(-1) for uncoated LiNi0.5Mn1.5O4, while 108 mAha (TM) g(-1) for carbon-coated LiNi0.5Mn1.5O4. The coated sample also exhibited excellent cyclic performance, remaining 95 % of its initial discharge capacity (131 mAha (TM) g(-1)) at 1 C rate after 100 cycles. The interfacial resistance of LiNi0.5Mn1.5O4 with carbon coating was reduced from 90 to 31 Omega.

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