Wu Lantao, Wang Jianshe, Shen Yi, Liu Le, Xi Jingyu
Institute of Green Chemistry and Energy, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
Phys Chem Chem Phys. 2017 Jun 7;19(22):14708-14717. doi: 10.1039/c7cp02581e.
Various testing methods, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), have been employed to evaluate the electrode performance of vanadium flow batteries (VFB). Due to the variations in the testing devices and characterization parameters in the literature, a number of reported results are incomparable and even sometimes contradictory. In this report, a reliable device is proposed for the electrochemical characterization of electrode materials, and the parameter selection was demonstrated to be critical for achieving reliable evaluation and reducing the effects of side reactions. As for the structure of the graphite felt electrode, volume current density is proposed to replace the area current density as the main evaluation indicator. Furthermore, the effect of side reactions is discussed and the upper limit voltage of 1.60 V is found to be suitable in the charge process of VFB since selecting this value can greatly protect the active sites on the electrode and avoid the capacity fading caused by side reactions.
已经采用了各种测试方法，如循环伏安法（CV）和电化学阻抗谱（EIS）来评估钒液流电池（VFB）的电极性能。由于文献中测试设备和表征参数的差异，许多报道的结果无法比较，甚至有时相互矛盾。在本报告中，提出了一种用于电极材料电化学表征的可靠设备，并证明参数选择对于实现可靠评估和减少副反应的影响至关重要。至于石墨毡电极的结构，建议用体积电流密度代替面积电流密度作为主要评估指标。此外，还讨论了副反应的影响，发现1.60 V的上限电压在VFB的充电过程中是合适的，因为选择这个值可以极大地保护电极上的活性位点，避免副反应导致的容量衰减。
