Phenanthraquinone-based polymer organic cathodes for highly efficient Na-ion batteries

A new organic polymer cathode namely poly(9,10-phenanthraquinone-alt-benzene) (PPQ, ~190 mAh g(-1)) is designed and synthesized for sodium-ion batteries (SIBs). Adequate characterizations are carried out to define its polymer nature. In half cells, the discharge capacity of PPQ shows almost no attenuation, stably maintaining at 150 mAh g(-1) during 300 cycles. In full cells, the PPQ II Na3Bi SIBs realize the stable discharge capacities of average 126 mAh g(cathode)(-1) during 150 cycles (100 mA g(cathode)(-1)) and average 97 mAh g(cathode)(-1 ) during 800 cycles (800 mA g(cathode)(-1)), along with the average discharge voltage of ~ 1.5 V. To the best of our knowledge, the results of PPQ can represent the new advancement for organic polymer cathodes in SIBs.