An all-organic symmetric battery based on a triquinoxalinylene derivative with different redox voltage active sites and a large conjugation system

Abstract

Organic materials are considered to have broad application prospects in energy storage systems due to their strong designability and abundant resources. Here, we report a triquinoxalinylene derivative tribenzoquinoxaline-5,10-dione (3BQ) containing high redox potential functional groups (CO and CN) and a large number of low redox potential functional groups (unsaturated carbon). This paper uses 3BQ as the cathode and anode to assemble all-organic symmetric batteries. Since 3BQ has denser active sites and a larger conjuated system than triquinoxalinylene (3Q), the 3BQ cathode has an initial capacity of 506 mA h g⁻¹ (C_theo = 515 mA h g⁻¹) at 0.2C, and the capacity of 3BQ and 3Q cathodes is 210 and 107 mA h g⁻¹ after 300 cycles at 1C. The large conjugated system and planar structure of 3BQ inhibit its dissolution in electrolytes and accelerate the charge transfer rate, resulting in good cycle stability and rate performance for batteries. The all-organic symmetric batteries assembled with pre-lithiated 3BQ and pristine 3BQ deliver an initial capacity of 483 mA h g⁻¹ at 0.2C, a capacity of 172 mA h g⁻¹ after 300 cycles and an energy density of 301 W h kg⁻¹. This work provides a strategy for the development of high-performance LIBs using organic materials as the cathode and anode.