Cycling decay mechanism and accelerated aging model of the sulfur-based lithium-ion batteries

Lithium–sulfur batteries suffer from rapid capacity decay due to polysulfide dissolution and lithium anode instability. Sulfurized poly(acrylonitrile) (SPAN), which chemically anchors sulfur within its polymer matrix, can effectively suppress polysulfide dissolution. Pairing SPAN with the graphite (Gr) anode can circumvent challenges associated with lithium metal and achieve prolonged cycle life. For developing such long-life sulfur-based batteries, it is of great significance to understand their cycling decay mechanism and establish a reasonable acceleration test model, since it is beneficial for quickly evaluating the cycle properties and optimizing battery designs. This study systematically investigates the electrochemical dynamics and capacity decay mechanism of SPAN∥Gr pouch cells cycled at 25–55 °C. Multiscale analyses reveal that capacity fade arises from active lithium loss and increased resistance, both of which would be accelerated by higher temperatures. Leveraging the consistent decay mechanism across temperatures, an accelerated aging model based on the Arrhenius equation is developed. This model could predict cycling parameters at specific temperatures and reduce testing time by 50%. These insights and the accelerated aging model may provide critical guidance for developing long-life sulfur-based batteries for practical applications. (Figure presented.).