Synthetic melanin facilitates MnO supercapacitors with high specific capacitance and wide operation potential window.

Although tremendous efforts have been devoted to manganous oxide (MnO)-based hybrid electrode materials, the rational design and facile preparation of high-performance MnO hybrid supercapacitors are still full of challenges, due to the inevitable agglomeration and limited stability of MnO within carbon matrixes. In this work, we developed a direct one-pot polymerization method to synthesize a series of Mn ion doped polylevodopa [P(L- DOPA)] synthetic melanin nanoparticles (Mn@SMNPs) for further transforming into small-sized hybrid carbon nanoparticles (MnO@CNPs, 20–80 nm) consisting of many stable Mn-related chemical bindings (C–N–Mn). The obtained MnO@CNPs electrode materials with physically spatial protection and well distribution of MnO could display high specific capacitance values (e.g., 545 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte) within a wide operation voltage of 1.3 V. This work will continue to provide an inspiration towards the fabrication of the next-generation of high-performance synthetic melanin-based energy storage materials and devices. [Display omitted] ● MnO@CNPs were prepared through a facile one-pot fabrication strategy with small size and high MnO doping content. ● The obtained MnO@CNPs with physically protection showed a well distribution of MnO. ● The stable C–N–Mn chemical binding structure facilitates the stabilization of MnO during the charging and discharging. [ABSTRACT FROM AUTHOR]