Self‐Templating Synthesis of 3D Hollow Tubular Porous Carbon Derived from Straw Cellulose Waste with Excellent Performance for Supercapacitors

A three‐dimensional hollow tubular porous carbon (SCPC) was prepared from straw cellulose waste through a self‐templating method combined with NaOH activation. Straw cellulose acts both as carbon source and structural template. The obtained SCPC exhibits a 3D hierarchical porous network structure. SCPC has a high specific surface area, a high mesoporosity ratio, and a low resistivity, which make it display excellent electrochemical performance for supercapacitors. SCPC showed a high specific capacitance of 312.57 F g −1 in 6  m KOH at 0.5 A g −1 , an excellent rate performance of 281.32 F g −1 even at 15 A g −1 , and an outstanding cyclic stability of 92.93 % capacitance retention after 20 000 cycles at 1 A g −1 . SCPC‐based supercapacitors can deliver an energy density of 8.67 Wh kg −1 at a power density of 3.50 kW kg −1 in 6  m KOH and an energy density of 28.56 Wh kg −1 at a power density of 14.09 kW kg −1 in 1  m Et 4 NBF 4 /PC, which demonstrates the possibility of applying SCPC in supercapacitors. This research not only offers a facile and sustainable method for the preparation of hierarchical porous carbon for electrochemical energy storage devices but also provides a highly efficient method for the utilization of biomass waste.