High-Performance n-Type Conducting Polymer-Based Supercapacitors with Enhanced Capacitance and Stability via Redox Additives

Conducting polymers, as a type of pseudocapacitive material, have garnered significant attention in the development of all-organic supercapacitors due to their superior electrochemical properties. While extensive research has been conducted on p-type conducting polymers, n-type analogues continue to face challenges such as poor stability and narrow electrochemical windows. This study presents a method to enhance n-type conducting polymer poly(benzodifurandione) (PBFDO)-based supercapacitors by introducing hydroquinone (HQ) as a redox-active electrolyte additive. With 20 mM HQ, an increase in specific capacitance from 33 to approximately 60 F g^-1 is observed, and the device retains over 93% capacity after 50,000 cycles. Experimental results demonstrate that HQ facilitates reversible doping/dedoping processes, thereby improving ion diffusion and polymer stability. Remarkably, even under an ultrahigh power density of 50,000 W kg^-1, the device still delivers 5.6 Wh kg^-1 of energy density, demonstrating exceptional high-power endurance. Similarly, other hydroquinone derivatives also improve rate capability and long-term stability, thereby mechanistically confirming the universality of this strategy for improving the performance of all-organic energy storage devices.