Distribution of relaxation times: Foundations, methods, diagnostics, and prognosis for electrochemical systems
Zilong Wang, Yuhao Wang, Francesco Ciucci
Abstract
The distribution of relaxation times (DRT) has become an indispensable technique for interpreting electrochemical impedance spectroscopy. This review traces the evolution of DRT from a powerful deconvolution tool for gaining mechanistic insight to a predictive engine for diagnostics and state estimation in fields such as batteries and fuel cells. The technique's intuitive appeal is challenged by its mathematically ill-posed nature, creating a "credibility gap" where subjective choices can yield misleading artifacts. Recent methodological advances in Bayesian and entropy-based frameworks provide greater robustness and uncertainty quantification. The path forward requires establishing a comprehensive analytical ecosystem built on community standards, benchmark datasets, and transparent reporting. This current opinion urges the community to embrace rigor and transform DRT from a specialized, expert-level tool into a reliable and reproducible cornerstone of electrochemical analysis.