Effect of Synthesis Temperature on Performance of Phenazine-Based Cathode for Sodium Dual-Ion Batteries

Organic materials have attracted much attention in the field of electrochemical energy storage due to their ecological sustainability, abundant resources and structural designability. However, low electrical conductivity and severe agglomeration of organic materials lead to poor discharge capacity and reaction kinetics in batteries. Herein, the morphology of the phenazine-based organic polymer poly(5,10-diphenylphenazine) (PDPPZ) was modified by varying the synthesis temperature. PDPPZ-165 °C with an exceptional porous structure provides abundant reaction channels for rapid charge transfer and diffusion that improves the reaction kinetics in sodium dual-ion batteries. Therefore, PDPPZ-165 °C cathode possesses excellent rapid charge-discharge capability delivering a specific capacity of 119.2 mAh g⁻¹ at 40 C. Furthermore, a high specific capacity of 124.7 mAh g⁻¹ can be provided even at a high loading of 16 mg cm⁻² at 0.5 C with a capacity retention of 86.4 % after 500 cycles. This work could afford new insights for optimizing the performance of organic cathode materials in sodium dual-ion batteries.