Two p-type ester-linked dihydrophenazine-based polymers as high-performance cathode materials for lithium-ion batteries

Dihydrophenazine (DHP)-based cathode electrode materials have been considered as distinctive candidates for next-generation green batteries. However, limited efficient and cost-effective synthetic approaches are available so far. Herein, two ester-linked DHP-polymers (PPDC and PPTC) are effectively achieved through typical esterification reactions from industrial waste product phenazine. As cathode materials for lithium ion batteries, PPDC and PPTC exhibit superior performance with high specific capacities up to 180 and 120 mA h g-1, respectively, at a current density of 0.2 A g-1, long-term cycling stability (capacity remains of 109 and 78 mA h g-1, respectively, after 1000 cycles at a current density of 1.0 A g-1), and high rate capability (141 and 64 mA h g-1, respectively, at 2 A g-1). Two novel redox-active ester-linked polymers were effectively achieved from an industrial waste product, phenazine, and exploited as sustainable superior organic cathode materials of lithium-ion batteries.