Schalenbach Maximilian, Durmus Y Emre, Tempel Hermann, Kungl Hans, Eichel Rüdiger-A
Fundamental Electrochemistry (IEK‑9), Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.
Sci Rep. 2022 Mar 1;12(1):3375. doi: 10.1038/s41598-022-07411-0.
Pseudocapacitances such as the hydrogen adsorption on platinum (HAoPt) are associated with faradaic chemical processes that appear as capacitive in their potentiodynamic response, which was reported to result from the kinetics of adsorption processes. This study discusses an alternative interpretation of the partly capacitive response of the HAoPt that is based on the proton transport of ad- or desorbed hydrogen in the double layer. Potentiodynamic perturbations of equilibrated surface states of the HAoPt lead to typical double layer responses with the characteristic resistive-capacitive relaxations that overshadow the fast adsorption kinetics. A potential-dependent double layer representation by a dynamic transmission line model incorporates the HAoPt in terms of capacitive contributions and can computationally reconstruct the charge exchanged in full range cyclic voltammetry data. The coupling of charge transfer with double layer dynamics displays a novel physicochemical theory to explain the phenomenon of pseudocapacitance and the mechanisms in thereon based supercapacitors.
诸如铂上氢吸附（HAoPt）之类的赝电容与法拉第化学过程相关，这些过程在其动电位响应中表现为电容性，据报道这是由吸附过程的动力学导致的。本研究讨论了基于双层中吸附或解吸氢的质子传输对HAoPt部分电容响应的另一种解释。HAoPt平衡表面状态的动电位扰动会导致典型的双层响应以及特征性的电阻 - 电容弛豫，这掩盖了快速吸附动力学。通过动态传输线模型的电位依赖双层表示法在电容贡献方面纳入了HAoPt，并且可以通过计算重建全范围循环伏安数据中交换的电荷。电荷转移与双层动力学的耦合展示了一种新颖的物理化学理论，用于解释赝电容现象以及基于其上的超级电容器中的机制。
