Electrochemical stability analysis of red phosphorus-based anode for lithium-ion batteries

Red phosphorus and sulfurized polyacrylonitrile (RP-SPAN) composite has recently shown promising results as an anode material in lithium-ion battery applications. However, the stability analysis of its dynamic response has not been investigated yet. In this study we use the transfer function stability analysis, the Kramers-Kronig (KK) integral relations, and the differential capacity analysis to evaluate the cell's behavior in both frequency and time domains in terms of stationarity, stability, linearity, as well as dissipation and degradation with extended charge/discharge cycling. The results show that the system is highly nonlinear and time-variant at the low-frequencies spectrum which is in line with the 0.21% average capacity loss per cycle computed from consecutive charge/discharge measurements. We propose using a modified constant phase element in which magnitude and phase, and thus real and imaginary parts of the spectral response are decoupled to fit the low-frequency, non-KK-compliant data. © 2021 Elsevier Ltd