| In order to investigate the effects on cycling rechargeability and capacity retention by Co added spinel LiMn₂O₄, the cyclic tests were peformed on the LiMn_(2-x)Co_xO₄ (x=0.05, 0.1, 0.2) cathode thin films fabricated by RF magnetron sputtering. Though the initial discharge capacity of LiMn_(2-x)Co_xO₄ were slightly lowered with increasing the Co contents in comparison with that of LiMn₂O₄, irreversible capacity loss greatly decreased and its stability on cycling was noticeably improved. The LiMn_(2-x)Co_xO₄, x=0.05, retained 97% of its initial capacity after 100 cycles while LiMn₂O₄ retains 88% of the initial capacity. Especially, discharge capacity of the composition LiMn_(2-x)Co_xO₄, x=0.05, after the 100 cycles is 49 ㎂h/㎠-㎛, which was superior to that of LiMn₂O₄, 46㎂h/㎠-㎛. These results indicated that the Co addition into LiMn₂O₄ improved the structure stability of spinel LiMn₂O₄. |
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