Synthesis and capacitive performance of two-dimensional sandwich-like graphene/nitrogen-doped carbon nanoparticle composites with tunable textural parameters and nitrogen content

Abstract

Two-dimensional sandwich-like graphene/nitrogen-doped carbon nanoparticle (G/N-doped C) composites with tunable textural parameters such as the specific surface area and the specific pore volume, and nitrogen content have been successfully prepared using graphene/porous SiO₂ composites as a template, and ethylenediamine (EDA) and carbon tetrachloride (CTC) with different weight ratios as nitrogen-containing carbon precursors using a simple nanocasting technology. The capacitive performance of the obtained materials has been tested in 1 M H₂SO₄ aqueous electrolyte. The optimum EDA to CTC weight ratio required for excellent capacitive performance is around 0.4. The G/N-doped C composites prepared with the EDA to CTC weight ratio of 0.4 exhibit a high capacitance of up to 189 F g⁻¹ at a current density of 0.1 A g⁻¹, attributed to the co-contribution of double layer capacitance and pseudocapacitance. They also show excellent rate capability (104 F g⁻¹ remained at 15 A g⁻¹) and cycle durability (nearly no capacity decay over 5000 cycles), making them promising electrode materials for supercapacitors.