A Low‐Temperature Dehydration Carbon‐Fixation Strategy for Lignocellulose‐Based Hierarchical Porous Carbon for Supercapacitors

Lignocellulose-based hierarchical porous carbon is a very promising electrode material for supercapacitors, but lower volumetric energy density and yield have hindered its practical applications. Herein, a low-temperature dehydration carbon-fixation method using NH4 Cl as modification reagent was developed to prepare rice husk-based hierarchical porous carbon (RHPC) with high volumetric performance and yield. The RHPC-N electrode exhibited a higher volumetric specific capacitance of 134.4 F cm-3 than that of the RHPC electrode (98.4 F cm-3 ) in 1 m Et4 NBF4 /propylene carbonate electrolyte. The volumetric energy density (28.8 Wh L-1 ) of the RHPC-N electrode was 37.1 % higher than that of the RHPC electrode (21.0 Wh L-1 ), which greatly enhanced the practical application potential of RHPC in supercapacitors. Moreover, the yield of RHPC increased 1.2 times by this method, which greatly improved the production capacity and reduced the cost. This research establishes a simple and highly efficient method to improve the volumetric energy density and the yield of lignocellulose-based hierarchical porous carbon.