Large-scale single-step synthesis of wrinkled N–S doped 3D graphene like nanosheets from Tender palm shoots for high energy density supercapacitors.

Herein, we present a simple, large-scale and low-cost process to develop hierarchically porous N–S co-doped 3D wrinkled graphene like nanosheets (3D H-GNS) from carbonization of biomass Tender palm shoots and NaHCO 3. Non-corrosive and non-toxic Na 2 CO 3 acts as a reaction mean to control the activation process, developing 3D H-GNS with a high specific surface area of 2095 m2 g−1. A 3D H-GNS-900 electrode exhibits a high specific capacitance of 529 F g−1 (1.5 A g−1) and 330 F g−1 (1 A g−1) in 1 M H 2 SO 4 for 3-electrode and 2-electrode systems respectively. Further, a longer cycle life with 93% capacitance retention over 10,000 cycles at 5 A g−1 is realized. Also, we are successful in fabricating biocompatible solid-state flexible supercapacitor device with 3D H-GNS-900 electrodes in organic electrolyte with 3 V voltage range, demonstrating to run a toy fan and lightning a LED for 15 min after charging for 60 s. Image 1 • Novel self N–S co-doped 3D wrinkled graphene like nanosheets (3D H-GNS) are developed from biomass Tender palm shoots. • As-prepared 3D H-GNS exhibit high specific surface area and unique porous morphology. • High specific capacitance of 529 F g−1 at 1.5 A g−1 and excellent energy density of 106.3 Wh kg−1 in organic electrolyte is achieved. • Fabricated fully bio-compatible solid-state flexible supercapacitor presents electrochemical stability up to 2000 bending angles. [ABSTRACT FROM AUTHOR]