Stabilizing sulfur doped manganese oxide active sites with phosphorus doped hierarchical nested square carbon for efficient asymmetric supercapacitor

Abstract

The introduction of heteroatom species into hollow carbon lattice networks (HCLN) and metallic oxides have been exploited as an effective approach to enhance the performance of the electrochemical electrodes. Herein, square hierarchical P-doped porous carbon/S-doped manganese oxide (S-Mn5O8@PPC) is designed via a solvothermal, chemical vapor deposition and wet chemical growth method from the solid-state gas-steaming operation of zinc of square acids, offering a unique nested hierarchical and stable integrated structure. As a result, the as-fabricated S-Mn5O8@PPC and PPC demonstrated impressive electrochemical capacitance of 1819.8F g−1 and 325.1F g−1 at 1 A g−1, respectively, which both superior than the Mn5O8@PPC and porous carbon (PC, 1604.0F g−1 and 193.2F g−1). Especially, the specific capacitance of the PPC is preferred to that of most non-metallic heteroatom-doped MOFs-derived carbons. More importantly, two supercapacitor (SC) electrodes - square hierarchical P-doped porous carbon (PPC) and S-doped manganese oxide coated PPC - are further self-assembled a hybrid SC device, which possesses a wide voltage of 0–1.6 V, outstanding electrochemical capacitance of 154.8F g−1, impressive energy storage performance and a reliable capacitive stability (87.24% after 5000 cycles), apart from the ideal energy density and power density (55.1 W h kg−1 at 800.0 W kg−1). Such excellent features originate from the large specific surface area of the porous hierarchical hollow structure, the doping of heterogeneous P and S, the dispersive loading of manganese oxide, and harmonious matching of positive and negative electrodes.