How carbon coating or continuous carbon pitch matrix influence the silicon electrode/electrolyte interfaces and the performance in Li‐ion batteries

Abstract

Abstract The Si surface coating by carbon is an appealing strategy to improve both the electronic conductivity and to stabilize the solid electrolyte interphase (SEI). In the present study, the electrochemical performance comparison of three nanocrystalline silicon‐based electrodes confirms the advantage brought by the carbon presence either as coating or in a composite, to improve their performance in Li‐ion batteries (LIBs). To rationalize this behavior, a full study of the electrode/electrolyte interface was achieved through the analysis of the cumulated relative irreversible capacity and the impedance and X‐ray photoelectron spectroscopies measurements. The study highlighted that the carbon coating leads to more efficient and less resistive SEI than that formed on silicon or on the native oxide surface. The pitch carbon matrix offers the same advantages and avoids moreover the isolation of particles. The control of the Si/electrolyte interface has a crucial role in the performance of Si‐based electrodes as negative electrodes for LIB.

Keywords

• batteries
• negative electrodes
• silicon