Impedance spectrocopy of carbonized and thermal activated porous carbon materials

Using the impedance spectroscopy method, a comparative analysis of the kinetics of the electrochemical insertion of lithium ions into a porous carbon material obtained by hydrothermal carbonization of plant raw materials at a temperature of 750°C (PCM-C sample) and its subsequent thermal activation at a temperature of 400°C for 2.5 h (PCM-TA sample) was carried out. For electrochemical systems based on these materials, equivalent electrical circuits were selected that satisfactorily model the impedance spectra in the studied frequency range of 10-2 -105 Hz. A physical interpretation was proposed for each element of the circuit. The diffusion coefficient of lithium ions into the structure of electrode materials was calculated.