For RR deconvolution, 𝜆 (given 𝑍 exp (𝑓)) was selected using all parameter selection methods described in Section 2.1.2 in the range from 10 -7 to 10 -1 by minimizing the corresponding score (Section 2.1.2.2). The vector 𝒙 was obtained by solving (2) using the 𝜆 values obtained using each model. For the hyper-𝜆 methods, 𝒙 was obtained through the alternate minimization algorithm described in Section 2.1.1.2. We must stress that the non-negativity constraint in (2) was not enforced for "hook" EIS spectra (Section 3.1.4). For all the methods, the DRT impedance, 𝒁 DRT , was computed using 𝒁 DRT = 𝑨𝒙.