Transient Charging of Mixed Ionic‐Electronic Conductors by Anomalous Diffusion

Mixed ionic‐electronic conductors (MIECs) play a pivotal role in energy storage, bioelectronics, and neuromorphic computing. Understanding charge transport dynamics in these materials is crucial for optimising device performance. This study investigates the transient charging behavior of three representative MIEC systems: PEDOT:PSS, electrochromic WO 3 , and n‐doped PBDF polymer films via electrochemical impedance spectroscopy (EIS) and transient current measurements, focusing on anomalous diffusion. By employing the transmission line model and fractional exponent fitting, a strong correlation is revealed between impedance response and transient current dynamics. The findings provide insights into the role of fractional diffusion in MIEC charge transport and inform the design of advanced electrochemical devices.