Anthraquinone based redox-active polymers for organic batteries

The development of new materials for energy storage systems plays an increasingly important role to compensate the growing demand for portable and flexible electronics. Redox-active organic compounds, in particular polymers, represent promising materials featuring many advantages such as flexibility, light-weight and being environmental friendly. Moreover, organic redox-active polymers can be produced at low temperature procedures from renewable or recycled resources and can be processed utilizing efficient and low-cost techniques (e.g., printing techniques). Anthraquinone-based polymers represent promising redox-active materials for the application in organic batteries or solar-rechargeable electric energy storage systems. The redox potential of anthraquinones can be tailored to the desired potential by straightforward modification of the carbonyl groups to electron donating or accepting groups (i.e., 1,3-dithiol-2-ylidene, N-cyanoimine, N,N-dicyanomethylene and thione group). Furthermore, a good charge-to-mass ratio is obtained due to the two electrons redox behavior, which results in comparably high theoretical capacities from 132 to 207 mAh/g. The introduction of low molar mass polymerizable groups, such as vinyl or ethynyl results in anthraquinone monomers that can be polymerized by straightforward polymerization techniques like free radical and rhodium-catalyzed polymerization, respectively. Lithium-organic batteries using the developed polymers as cathode material show promising charge/discharge behaviors with good cycling stability. The present results contribute to the understanding of the relationship between structure and electrochemical behavior and show new perspectives for the development of polymers with tailor-made redox potentials for novel redox-active materials in organic electronics.