Phenazinyl polymer@rGO composite cathode materials with fast charging and wide temperature adaptability for sodium dual-ion batteries

Abstract

Sodium dual-ion batteries (SDIBs) have garnered significant interest owing to the abundant and low-cost of sodium resources. Flexible organic materials are considered promising SDIBs cathodes due to their tunable structures and multi-electron redox properties. However, poor solubility, low conductivity, and particle agglomeration limit their practicality. Herein, a composite poly(5, 10-diphenylphenazine)@rGO (PDPPZ@rGO) was designed for the cathode of SDIBs. The rGO matrix enhances PDPPZ's dispersibility and active surface area while providing high conductivity and mechanical stability, resulting in superior electrochemical performance. Consequently, the PDPPZ@rGO electrode demonstrates a remarkable discharge capacity of 175.8 mAh g^-1, excellent rate performance (128.9 mAh g^-1 at 40 C), and outstanding cyclic stability (capacity retention of 85.1% after 5000 cycles at 10 C). Furthermore, PDPPZ@rGO has excellent wide temperature adaptability, outputting a specific capacity of 157.7 mAh g^-1 at high temperatures of 60 °C and 145.2 mAh g^-1 at low temperatures of -20 °C. This research demonstrates the potential of organic cathode materials for rapid charge/discharge capabilities and wide temperature adaptability in SDIBs.