Synergy of Nyquist and Bode Electrochemical Impedance Spectroscopy Studies to Assess the Effect of Morphology on the Electrochemical Properties of Li-Ni-Mn-Al-O Materials

2017 ◽  
Vol 2 (21) ◽  
pp. 6090-6096
Author(s):  
Hongxu Lin ◽  
Chenghao Liang ◽  
Chaojun Liu ◽  
Changsong Dai ◽  
Yueping Xiong
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Properties ◽  
Electrochemical Impedance ◽  
Spectroscopy Studies

scholarly journals Studies on Anion Exchange Membrane and Interface Properties by Electrochemical Impedance Spectroscopy: The Role of pH

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 771
Author(s):  
Wenjuan Zhang ◽  
Wei Cheng ◽  
Ramato Ashu Tufa ◽  
Caihong Liu ◽  
David Aili ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Ion Exchange ◽  
Electrochemical Properties ◽  
Anion Exchange ◽  
Structural Changes ◽  
Electrochemical Impedance ◽  
Transport Processes ◽  
Anion Exchange Membranes ◽  
Interface Properties

Ion-exchange membranes (IEMs) represent a key component in various electrochemical energy conversion and storage systems. In this study, electrochemical impedance spectroscopy (EIS) was used to investigate the effects of structural changes of anion exchange membranes (AEMs) on the bulk membrane and interface properties as a function of solution pH. The variations in the physico/electrochemical properties, including ion exchange capacity, swelling degree, fixed charge density, zeta potentials as well as membrane and interface resistances of two commercial AEMs and cation exchange membranes (CEMs, as a control) were systematically investigated in different pH environments. Structural changes of the membrane surface were analyzed by Fourier transform infrared and X-ray photoelectron spectroscopy. Most notably, at high pH (pH > 10), the membrane (Rm) and the diffusion boundary layer resistances (Rdbl) increased for the two AEMs, whereas the electrical double layer resistance decreased simultaneously. This increase in Rm and Rdbl was mainly attributed to the deprotonation of the tertiary amino groups (-NR2H+) as a membrane functionality. Our results show that the local pH at the membrane-solution interface plays a crucial role on membrane electrochemical properties in IEM transport processes, particularly for AEMs.

Sign in / Sign up

Export Citation Format

Share Document