Ultrastable dihydrophenazine-based polymer from industrial waste as a sustainable lithium-ion battery cathode material

Abstract

Full utilization of chemical industrial waste is critical to ecological and social sustainability. Amongst the various waste materials, it is rather fascinating to utilize redox-active organic waste products as sustainable electrode materials for rechargeable lithium-ion batteries (LIBs). In this work, a novel p-type dihydrophenazine-based polymer, poly(5,10-bis-(ethyl methacrylate)-phenazine) (PBEMP), was synthesized as an organic LIB cathode material from the industrial by-product phenazine, which is currently disposed of by burning, releasing about 3500 tonnes of carbon dioxide to the environment annually as well as other gaseous wastes. PBEMP exhibits a high average working potential (up to 3.37 V vs. Li/Li⁺), superior rate capability, ultra-high cycling stability (after 1000 cycles at 1.0 A g⁻¹, 77% of the initial capacity is retained), high specific capacity (123 mA h g⁻¹) and a high specific energy of 413.7 W h kg⁻¹. This work provides a feasible strategy to utilize phenazine as a useful material, avoiding the release of massive amounts of environmentally unfriendly gases.