Zhu Yuanyuan, Ji Xu, Cheng Shuang, Chern Zhao-Ying, Jia Jin, Yang Lufeng, Luo Haowei, Yu Jiayuan, Peng Xinwen, Wang Jenghan, Zhou Weijia, Liu Meilin
New Energy Research Institute, School of Environment and Energy , South China University of Technology , Guangzhou 510006 , China.
College of Automation , Zhongkai University of Agriculture and Engineering , Guangzhou 510225 , China.
ACS Nano. 2019 Aug 27;13(8):9091-9099. doi: 10.1021/acsnano.9b03324. Epub 2019 Aug 12.
While pseudocapacitive electrodes have potential to store more energy than electrical double-layer capacitive electrodes, their rate capability is often limited by the sluggish kinetics of the Faradaic reactions or poor electronic and ionic conductivity. Unlike most transition-metal oxides, MoO is a very promising material for fast energy storage, attributed to its unusually high electronic and ionic conductivity; the one-dimensional tunnel is ideally suited for fast ionic transport. Here we report our findings in preparation and characterization of ultrathin MoO sheets with oriented tunnels as a pseudocapacitive electrode for fast charge storage/release. A composite electrode consisting of MoO and 5 wt % GO demonstrates a capacity of 1097 C g at 2 mV s and 390 C g at 1000 mV s while maintaining ∼80% of the initial capacity after 10,000 cycles at 50 mV s, due to minimal change in structural features of the MoO during charge/discharge, except a small volume change (∼14%), as revealed from Raman spectroscopy, X-ray analyses, and density functional theory calculations. Further, the volume change during cycling is highly reversible, implying high structural stability and long cycling life.
虽然赝电容电极比双电层电容电极具有存储更多能量的潜力，但其倍率性能往往受到法拉第反应缓慢动力学或较差的电子和离子导电性的限制。与大多数过渡金属氧化物不同，MoO是一种非常有前途的快速储能材料，这归因于其异常高的电子和离子导电性；一维隧道非常适合快速离子传输。在此，我们报告了我们在制备和表征具有定向隧道的超薄MoO片作为赝电容电极用于快速电荷存储/释放方面的研究结果。由MoO和5 wt%的氧化石墨烯组成的复合电极在2 mV s时表现出1097 C g的比容量，在1000 mV s时为390 C g，并且在50 mV s下进行10000次循环后仍保持约80%的初始容量，这是由于在充放电过程中MoO的结构特征变化极小，除了有小的体积变化（约14%），这通过拉曼光谱、X射线分析和密度泛函理论计算得以揭示。此外，循环过程中的体积变化是高度可逆的，这意味着其具有高结构稳定性和长循环寿命。
