Monitoring the length change of Ni@C composite electrodes during charging/discharging processes
Monitoring the length change of Ni@C composite electrodes during charging/discharging processes
复制标题
监测Ni@C复合电极在充放电过程中的长度变化
DOI：
10.1016/j.elecom.2019.05.012
复制
发表时间：
2019-06-01
影响因子：
5.4
通讯作者：
Deng, Qibo
中科院分区：
文献类型：
--
作者：
An, Cuihua;Dong, Chenhao;Deng, Qibo
电极材料在电化学充放电过程中的体积迭代变化通常会导致电化学电容器性能下降。本工作研究了电极材料在电化学充放电过程中的机械稳定性，这可通过原位膨胀测量技术进行监测，重点关注电极的长度变化。作为一个简单的模型，制备了具有核 - 壳结构的多孔Ni@C复合材料作为电化学电容器的电极，它在稀电解质中表现出优异的电化学循环稳定性。Ni@C电极的这种稳定性可能得益于电化学循环过程中较小的长度变化。实验结果表明，电极响应电极表面电荷状态的膨胀和收缩具有弱不对称性。这种不平衡应变状态的发现可能有助于更好地理解电化学电容器的性能下降。
The iterative volume change of electrode materials during electrochemical charging/discharging processes could generally result in the performance degradation of electrochemical capacitors. This work investigates the mechanical stability of the electrode material during the electrochemical charging/discharging processes, which can be monitored by means of in situ dilatometry technique with a focus on the length change of the electrode. As a simple model, the porous Ni@C composite was prepared with a core-shell structure as the electrode for electrochemical capacitor, which exhibits excellent electrochemical cycling stability in a dilute electrolyte. This stability of Ni@C electrode may benefit from the small length change during the electrochemical cycling. The experimental results exhibit that the expansion and contraction of the electrodes in response to the charge state at the surface of the electrode is weakly asymmetric. This finding of an unbalanced strained state may contribute to a better understanding of the performance degradation of electrochemical capacitors.