Impedance Investigation of Silicon/Graphite Anode during Cycling

Abstract

Silicon/graphite material is one of the most promising anodes for high-performance lithium-ion batteries. However, the considerable deformation occurring during the charge/discharge process leading to its degradation hinders its application. Research on the electrochemical performance of silicon/graphite anode have mainly focused on its cyclic performance and microscopic mechanism, whilst the correlation between electrochemical performance and the mechanical deformation of batteries at the cell level is in few numbers. In this study, the electrochemical performance and cycling performance of the cells in Ah-level silicon/graphite anode pouch cells with different SiO weight ratios (5 wt.%, 10 wt.%, and 20 wt.%) in the anode, and LiNi0.8Co0.1Mn0.1 as the cathode are investigated by quantitative analysis. It is found that cells with different SiO weight ratios in anodes under a different state of charge (SOC) and state of health (SOH) demonstrate remarkable differences in electrochemical impedance characteristics. The results show that SOC, SOH and the weight ratios of SiO are the main factors affecting the impedance characteristics for batteries with silicon/graphite anode, which is deeply related to the change in the thickness of the electrode during lithiation/delithiation. This research facilitates the application of EIS in battery management and the design of silicon/graphite anode lithium-ion batteries.

Para Grass-Derived Porous Carbon-Rich SiOx/C as a Stable Anode for Lithium-Ion Batteries

“…After 200 cycles, the increase in R s indicates the electrolyte decomposition reaction during cycling, resulting in charge carrier loss and increasing solvent viscosity . Minimum SEI formation during cycling can be seen with minimum changes in the R SEI and R CT values . The large carbon content and high porous structure of the para grass SiO x /C electrode can contribute to stabilizing the SEI layer, enhancing the cycling stability. , …”

“…49 Minimum SEI formation during cycling can be seen with minimum changes in the R SEI and R CT values. 50 The large carbon content and high porous structure of the para grass SiO x /C electrode can contribute to stabilizing the SEI layer, enhancing the cycling stability. 16,29 Figure 5d displays the behavior of the para grass-derived SiO x /C anode under different current densities.…”

Investigation of the Influence of Silicon Oxide Content on Electrolyte Degradation, Gas Evolution, and Thickness Change in Silicon Oxide/Graphite Composite Anodes for Li-Ion Cells Using Operando Techniques

“…The key areas of focus include aging phenomena such as thickness change and gas analysis investigated in operando and also with post mortem analysis. The aging investigations will delve into the degradation mechanisms that occur within Si-containing anodes with varying silicon content, investigated during formation cycling, examining the impact of capacity loss, rate capability, impedance growth, and morphological changes [8,9]. Additionally, the paper will discuss the challenges posed by thickness change in silicon-containing anodes, addressing issues such as mechanical stress, electrolyte degradation, and gas evolution.…”