Improvement of cycle stability at elevated temperature and high rate for LiNi0.5−xCuxMn1.5O4 cathode material after Cu substitution

A series of Cu-substituted LiNi0.5−xCuxMn1.5O4 (x = 0, 0.03, 0.05 and 0.08) spinels have been synthesized using a sol–gel method. The results demonstrate that when x = 0.05, the sample (LiNi0.45Cu0.05Mn1.5O4) exhibits the best electrochemical performance, achieving 124.5 mAh g−1 and 115.0 mAh g−1 at the discharge rates of 5 C and 20 C with the capacity retention of 97.7% and 95.7% after 150 cycles, respectively. Besides, the excellent cycle stability at 55 °C has been demonstrated to retain 96.8% of the maximum attainable discharge capacity (127.3 mAh g−1) at the discharge rate of 5 C after 100 cycles. These data indicate that the LiNi0.45Cu0.05Mn1.5O4 cathode material has the real potential to be used for high power and high energy lithium ion battery in electric vehicle applications.

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► A series of LiNi0.5−xCuxMn1.5O4 cathode materials were synthesized via a sol–gel method.
► The improvement of cycle stability at 55 °C by Cu substitution is firstly reported.
► The LiNi0.45Cu0.05Mn1.5O4 material could achieve 115 mAh g−1 at 20 C discharge rate.
► The capacity retention at 55 °C is 98% after 100 cycles at 5C discharge rate.