Sustainable Polyurethane‐Derived Heteroatom‐Doped Electrode Materials for Advanced Supercapacitors

Abstract This work presented a new method to recycle rigid polyurethane foam (RPUF) waste. A two‐step method to carbonize and activate RPUF was applied to synthesize sustainable polyurethane‐derived N, O co‐doped electrode materials for supercapacitors (SCs). Structural characterization showed a three‐dimensional honeycomb‐like pore structure rich with micro/mesopores formed with a 3647 m 2 g −1 maximum specific surface area (SSA), and 2.04 at.% N and 8.30 at.% O were successfully co‐doped into the polyurethane porous carbons (PPCs). These properties created synergistic effects that enhanced the ion storage capacity and pseudocapacitance of the synthesized PPCs. As a result, the optimal PPC‐500‐800‐3 yielded excellent maximum specific capacitance in a three‐electrode (487 F g −1 ) and symmetric SC (324 F g −1 ) systems in a 1 m H 2 SO 4 electrolyte at 1 A g −1 current density. Moreover, for the LiTFSI/H 2 O/(ACN) 3.5 electrolyte, PPC‐500‐800‐3 produced a maximum energy density of 29.36 W kg −1 in a symmetric SC. After 10,000 cycles, PPC‐500‐800‐3 could achieve high cycling stability, maintaining 96.8 % of the initial capacitance at a 5 A g −1 current density.