Mild fabrication of SiC/C nanosheets with prolonged cycling stability as supercapacitor

A facile and mild route to synthesize C-coated SiC nanosheets(SiC/C NSs)via wet-chemical etching in hydrofluoric acid(HF)at 60°C for 48 h using carbon aluminum silicate(Al_(4)SiC_(4))as raw materials is reported for the first time.HF molecule leads to the breaking of C-Al bonds in Al_(4)SiC_(4),which eventually results in the formation of two-dimensional SiC nanosheets.A carbon layer with a thickness of approximately 1.5 nm is formed on the surface of SiC nanosheets due to the excess carbon.The prepared SiC/C NSs possess a smooth and rectangular sheet with a mean 150 nm in width,500 nm in length and10 nm in thickness,respectively.The crystallographic characterization indicates that 3C-SiC and 2H-SiC coexist and the parallel plane relationship of 3C/2H-SiC heterojunction is(111)_(3C-SiC)//(001)_(2H-SiC).Due to the formed 3C-SiC/2H-SiC heterojunction and graphitic carbon,the fabricated electrode based on SiC/C NSs exhibits prolonged cycling stability and high specific areal capacitance as a promising supercapacitor candidate.It remains 91.2%retention even after 20,000 cycles and 734μF/cm^(2)at a scan rate of 10 m V/s.