Voltage-Window-Tuned Lithium Storage Behavior of Poly(p-phenylenediamine) Analogue Anode

The development of high-performance organic electrode materials for lithium-ion batteries (LIBs) remains critical challenges such as capacity decay, dissolution, and poor cycling stability. Herein, we report a novel sulfur- and nitrogen-rich poly(p-phenylenediamine) analogue (PPPDA) synthesized by oxidative polymerization of 2,5-diamino-1,4-benzenedithiol dihydrochloride (DABDT), which is used as an anode material for LIB. The PPPDA exhibits a unique nanostructure, offering high surface area and abundant active sites. More importantly, this conjugated polymer provides multi-electron redox centers, demonstrating outstanding performance. The as-prepared PPPDA anode delivers reversible specific capacities of 1220 and 522 mAh g^-1at current densities of 1and 40 A g^-1, respectively, along with the prolonged cycling stability (982 mAh g^-1 after 1300 cycles at 5 A g^-1). Interestingly, PPPDA anode displays a voltage-dependent electrochemical behavior, requiring initial activation within a range of 0.01-3 V for optimal capacity maintenance in the 1-3 V operating window. This work highlights the potential of conjugated polymers as high-capacity alternatives to conventional anodes and offers design strategies for advanced organic anode materials.