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 m2 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 H2SO4 electrolyte at 1 A g−1 current density. Moreover, for the LiTFSI/H2O/(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.