Structure Characterizations and Electrode Performance of Poly(ethylene diaminoquinone) in Lithium-Organic Batteries

Redox-active polymers are promising alternatives to traditional-metal-based electrode materials and, in particular, for use as sustainable and flexible energy storage. Quinone-containing polymers are of great interest in the field due to their adjustable electrochemical properties through chemical modification of the polymer chains. Herein, a quinone-amine polymer, poly(ethylene diaminoquinone) (PEDQ), was synthesized through condensation-polymerization via a 1,4-Michael addition and oxidation reaction sequence. The polymer was characterized via different techniques, revealing the coexistence of hydroquinone and quinone units and proving the formation of a protonated amine and quinhydrone complex. When applied as the cathode in a lithium battery, PEDQ delivered a stable capacity of 220 mAh g^-1 for over 150 cycles, exceeding previous analogues. The nonconjugated backbone and short linkage afford the high capacity, excellent rate performance, and cyclability, allowing structural insights into the design of other quinone-based redox-active polymer electrode materials.