锂离子蓄电池用Cu-Sn合金负极的制备及改性

Preparation and improvement of Cu-Sn alloy negative electrode for lithium ion batteries

用机械合金化法经20h、50h和100h球磨制备了3种Cu-Sn合金,由合金制备的电极经300℃、500℃和700℃热处理后具有良好的电化学性能,其中经300℃热处理5h的电极具有最优的循环性能:电极循环50次后放电容量为205mAh·g-1以上,库仑效率为99.5%;电极循环100次后放电容量还有152mAh·g-1左右,库仑效率仍能维持在约99.5%,并且电极自放电率很小。

Cu-Sn alloy powders prepared by mechanical alloying for different periods were examined as a negative electrode for lithium ion batteries. Electrodes which were annealed at 300 ℃, 500 ℃ and 700 ℃ showed excellent electrochemical performance. Among these annealed electrodes, electrodes which were annealed at 300 ℃ for 5 h showed the best cycle performance. A stable reversible capacity of about 205 mAh·g-1 was obtained and coulombic efficiency maintained at 99.5% for 50 cycles. After 100 cycles, capacity of 152 mAh·g-1 was delivered and coulombic efficiency was the same as the value before 50 cycles. In addition, tests of electrochemical impedance spectrum demonstrated that these alloy electrodes had low self-discharge efficiency.