Fig. 5: Ex situ physicochemical characterizations of various potassium metal-based electrodes.
From: Codoped porous carbon nanofibres as a potassium metal host for nonaqueous K-ion batteries
Ex situ SEM images of a–d bare K and e–h MSCNF-K anodes from symmetric cells at different cycle numbers. Ex situ XPS spectra of i C 1 s, j O 1 s and k F 1 s from symmetric cells based on Cu-K anodes at different cycle numbers (Fresh, after the 1 st charge, and after the 20th charge). Ex situ XPS spectra of l C 1 s, m O 1 s and n F 1s from symmetric cells based on MSCNF-K anodes at different cycle numbers (Fresh, after the 1st charge, and after the 20th charge). The ex situ electrodes were sampled at an intermediate state of potassiation. All electrochemical measurements were carried out at a temperature of 25 ± 2 °C.
