Approach for Mitigating Interfacial Degradation in Silicon-Based Electrodes to Enhance Cycling Stability of Lithium-Ion Batteries and Capacitors

Abstract

The growing demand for high energy density in lithium-ion batteries has led to extensive investigations on silicon negative electrodes. In this study, we propose a novel approach to address the interfacial degradation of electrodes caused by volume expansion during lithium insertion/extraction. The approach involves a sandwich structure consisting of a carbon nanofiber (CNF) undercoating electrode and a CNF-coated separator. The CNF is treated with acid to form carboxyl and hydroxyl groups on its surface, which improves the dispersion of the coating slurry and enhances adhesion to the electrode. Through electrochemical testing, the improved silicon electrode shows a high retention rate of 82% compared to the initial capacity after 100 cycles, and high electrochemical performance when applied to both lithium-ion batteries and lithium-ion capacitors. These results are attributed to the improved adhesion between the electrode and current collector, as well as the formation of a stable solid electrolyte interphase layer on the electrode surface. These findings suggest that the conductive coating process, applied to the separator and current collector, effectively mitigates interfacial issues that are associated with silicon-based electrodes. This approach has the potential to overcome the degradation characteristics of silicon electrodes and significantly contribute to improving the cycling stability of lithium-ion batteries and capacitors.