Constructing efficient SPAN based energy storage batteries via the introduction of Cu2S-Li2S displacement reaction

Sulfurized polyacrylonitrile (SPAN), as an inherently safe, low-cost, and long-cycle-life material, holds a promising future in large-scale energy storage applications. However, there are still issues such as sluggish electrochemical reaction kinetics and low energy utilization efficiency, which severely constrain practical applications. Herein, we introduce the displacement reaction of Cu 2 S-Li 2 S to the conversion reaction of SPAN/Li 2 S by incorporating Carbon Nanotube (CNT) and Copper (Cu) to fabricate Cu-SPAN/CNT cathode. Detailed experimental investigations demonstrate the fast and reversible Cu 2 S-Li 2 S displacement reaction, enhancing the SPAN/Li 2 S redox kinetics. Consequently, Cu-SPAN/CNT achieves 1450 mAh g −1  at 1 C with 80.3 % retention after 1000 cycles, while delivering 1207 mAh g −1  at 4 C and maintaining operation under practical conditions (6.75 mg cm −2 sulfur loading, −20 °C). Crucially, it attains 79.8 % energy utilization efficiency at the 100th cycle. In conclusion, this work optimizes the cycling process of SPAN-based batteries, particularly the highly polarized charging processes, providing a simple solution for developing energy storage applications with extended cycle life, accelerated reaction kinetics, and enhanced energy utilization efficiency.