Serendipitous Synthesis and Ultrahigh Capacitance of Protonated C3n5 Nanosheets in Symmetric Super Capacitors

Abstract

Carbon nitride has recently transpired as the inevitable two-dimensional polymeric layered material tailoring in various fields due to its chemical stability and tunable band gap. Herein, the facile & scalable synthesis through the thermal polymerization of 3-amino-1, 2, 4-triazole precursor serendipitously forms another stable allotrope C3N5. An ultrathin C3N5 nanosheet was fortuitously achieved through the protonation process. Because of its electron-rich character and delamination of the stacked interlayer, the hydrochloric acid-treated C3N5 is endowed with ultra high capacitance and impressive cyclic stability outperforming the other carbon & metal oxides based material. As a result, it attains a high specific capacitance of 875 F/g, which is eight-fold higher than the pristine C3N5 and other acids treated C3N5. It also displayed excelled cyclic stability of 100% over 10,000 cycles. Furthermore, the fabricated symmetric device demonstrated remarkable power and energy densities of 72 W/kg and 19 Wh/kg, respectively, with excellent cyclic stability of 90% over 5000 cycles. The rate capability & improved capacitance of hydrochloric acid-treated C3N5 is due to the effective construction of charged ions from synergistically interplayed effect of segregated stacked interlayer with their electron rich nitrogen moieties.

Keywords: Nanosheets, Protonation, Super capacitor, C3N5, Carbon nitride, Energy storage