A novel polyquinone cathode material for rechargeable lithium batteries

A novel polymer, poly(5-amino-1,4-dyhydroxy anthraquinone) (PADAQ) as the cathode material of lithium batteries is synthesized by a facile oxidation process and characterized by FT-IR, MS, elementary analysis, XRD, SEM and electrochemical method. The results show that the as-prepared polymer solves the problems of dissolution and crystallization of its monomer, 5-amino-1,4-dyhydroxy anthraquinone (ADAQ), thus maintains the stability of the electrode structure successfully. At the cutoff voltage of 1.5-3.7 V, the initial discharge capacity of PADAQ is 101 mAh g^-1 at the current density of 400 mAh g^-1. After 14 cycles, the capacity increases to 143 mAh g^-1, and maintains 129 mAh g^-1 after 50 cycles, which shows an improved cycle performance compared to its monomer. Even at the high current density of 1400 mAh g^-1, its capacity still reaches 95 mAh g^-1, indicating a high rate capacity. The results also show that PADAQ is sensitive to discharge depth. When discharged to 1.0 V, its cycle performance is poor.