Fast charge rate supercapacitors based on nitrogen-doped aligned carbon nanosheet networks

Achieving high electrochemical energy density while retaining high power density still remains a great challenge for porous carbons as the electrodes for supercapacitors. We report a facile and scalable synthesis of N-doped aligned carbon nanosheet network (N-ACN10) with high surface area and efficient 3D ion and electron transport pathways. Moreover, 3D interconnected nanochannels parallel to the graphene planes are beneficial for the increased ion accessible surface area and fast ion diffusion. Benefiting from fast ion and electron transport kinetics, the N-ACN10 electrode exhibits excellent frequency response with a scan rate up to 5 V s⁻¹, high capacitance of 331 F g⁻¹ at 2 mV s⁻¹ and superior rate capability (203 F g⁻¹ at 5 V s⁻¹), as well as excellent cycling stability (98% of capacitance retention after 10,000 cycles) in 6 M KOH. More importantly, the assembled N-ACN10//N-ACN10 supercapacitors exhibit outstanding electrochemical performances in 1 M Na₂SO₄ and EMIMBF₄ electrolytes with maximum energy densities of 20.6 and 120.4 Wh kg⁻¹ based on the mass of total active material, respectively.