Chemical analysis of Li–CICs and electrochemical performance before and after electrochemical lithiation for Li-ion capacitor application

Abstract

For Lithium-Ion Capacitors (LIC), the power density or rate performance are often greatly limited by the anode material. This limitation arises from the difference in the energy storage mechanism between the anode and cathode, energy storage capacities, and the total amount of lithium present in the capacitor system. Therefore, pre-lithiation, which introduces a large quantity of lithium into the anode, is crucial strategy for enhancing LIC performance. For this study, Lithium–Carbon intercalation Compounds (Li–CICs) were synthesized by electrochemically. The lithium salts formed during the synthesis and subsequent electrochemical cell testing play an important role in determining battery performance. According to analysis confirmed that these salts generate from the reaction of lithium with functional groups on the surface of electrode material. The resulting compounds were analyzed using XRD, SEM (EDX), HRTEM, Raman, XPS, and BET techniques. These results are presented to facilitate future studies on the mechanism of electrochemical side reactions. This research characterizes and compares electrodes before and after short-term electrochemical lithiation using three electrode types to investigate the correlation between the degree of lithiation and energy storage capacity. Electrode performance was evaluated through cyclic voltammetry (CV), capacity measurements, electrochemical impedance spectroscopy (EIS), electrode resistance, specific capacitance, energy density, and power density. The half-cell tests demonstrated that all electrochemical properties were enhanced following the lithiation process.it following the lithiation process.