钠金属负极近常温退火工作的长寿命电池

Sodium-metal cathode annealing at near room-temperature for long life batteries

  • 摘要: 钠(Na)金属电池在充电过程中,正极的Na+得电子被还原成金属沉积在负极表面,随着电池的循环,沉积物不断增多,逐渐形成枝晶,影响电池寿命。本文利用Na金属低熔点(97 ℃)特性,借助近常温将已成型枝晶的电池在工作时退火,重新“再结晶”成均匀平整的金属,沉积在Na负极表面。因此,以磷酸钒钠(NVP)为正极的Na金属电池,在1 C倍率下循环300次后,放电比容量依然保持在83.8 mAh/g。说明35 ℃近常温热处理退火工作消除了枝晶,形成了无枝晶的负极表面,进而提升电池的电化学性能。

     

    Abstract: In the process of charging a sodium (Na) metal battery, the electrons of the positive Na+ are reduced into metal and deposited on the surface of the cathode. With the cycle of the battery, the sediment continuously increases and gradually forms the dendrite, limiting the battery life. In this study, the Na metal cathode was worked at near room temperature (35 ℃) at an annealing condition for recrystallization. Due to the low melt point (97 ℃), the metallic Na with dendritic-free plated on the cathodes was obtained. Accordingly, the sodium vanadium phosphate (NVP)||Na full cell indicated a discharge-specific capacity of 83.8 mAh/g even after 300 cycles at a C-rate of 1C. The results show that the working condition of 35 ℃ near room-temperature thermal treatment eliminates the dentrites and forms a cathode surface without the dentrite, thus improving the battery's electrochemical performance.

     

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