A redox-active polymer material for superior capacitive storage in ionic liquid electrolyte

Supercapacitors based on ionic liquid (IL) electrolytes offer realistic possibilities for high-performance and sustainable energy storage systems with their unique electrochemical properties, especially wide operation voltage and high usage security. However, there is still a lack of suitable capacitive-storage electrode materials in IL electrolytes. Herein, we have synthesized a highly redox-active polymer (PDPPZ) material with extended conjugated imine-based backbones for superior capacitive storage. Theoretical calculations, such as localized orbital locator-& pi; (LOL-& pi;) and molecular orbital techniques, reveal extraordinary electron delocalization and excellent electron affinity throughout the highly extended & pi;-conjugated polymeric backbones. As a result, the PDPPZ polymer as an organic electrode possesses a high capacitive storage of 135.6 F g-1 and long-term stability with as low as 0.003% decline per cycle in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) IL electrolyte, evidencing its shining in the electrochemical energy storage field.