Isolated Boron and Nitrogen Sites on Porous Graphitic Carbon Synthesized from Nitrogen‐Containing Chitosan for Supercapacitors

Abstract

Separated boron and nitrogen porous graphitic carbon (BNGC) is fabricated by a facile hydrothermal coordination/ZnCl2-activation process from renewable and inexpensive nitrogen-containing chitosan. In this synthetic pathway, chitosan, which has a high nitrogen content, first coordinates with Fe(3+) ions to form chitosan-Fe that subsequently reacts with boric acid (boron source) to generate the BNGC precursor. After simultaneous carbonization and ZnCl2 activation followed by removal of the Fe catalyst, BNGC, containing isolated boron and nitrogen centers and having a high surface area of 1567 m(2) g(-1) and good conductivity, can be obtained. Results indicate that use of chitosan as a nitrogen-containing carbon source effectively prevents nitrogen atoms from direct combination with boron atoms. In addition, the incorporation of Fe(3+) ions not only endows BNGC with high graphitization, but also favors for nitrogen fixation. Remarkably, the unique microstructure of BNGC enables its use as an advanced electrode material for energy storage. As electrode material for supercapacitors, BNGC shows a high capacitance of 313 F g(-1) at 1 A g(-1), and also long-term durability and coulombic efficiency of >99.5 % after 5000 cycles. Notably, in organic electrolytes, the energy density could be up to 50.1 Wh kg(-1) at a power density of 10.5 kW kg(-1). The strategy developed herein opens a new avenue to prepare BNGC without inactive BN bonds from commercially available chitosan for high-performance supercapacitors.

Porous NiCoP nanowalls as promising electrode with high-area and mass capacitance for supercapacitors

“…Especially, the porous NiCoP sheets have shown a high specific capacitance of 1,206 F g −1 (1 A g −1 ), superior to NiCo hydroxide (566 F g −1 ) [13]. Nevertheless, the powder materials should be "adhered" to the current collector by binders [35][36][37][38] which reduce the loading amount of active species, but are not favorable for effective contact of active materials with current collectors [39]. All the factors are detrimental to the applications of the materials.…”

Nitrogen‐Containing Carbon Aerogels with High Specific Surface Area for Supercapacitors

“…[15] Sun prepared B/N co-doped carbon aerogels with ZnCl 2 activation, which has a specific surface area of 1567 m 2 g À 1 and a specific capacitance of 313 F g À 1 at a current density of 1.0 A g À 1 . [16] In addition, KOH and CO 2 are commonly used to activate carbon aerogels. [17][18][19][20] However, activation often require additional steps, so it has great value to make carbonization and activation simultaneously.…”

Lamellar-structured biomass-derived phosphorus- and nitrogen-co-doped porous carbon for high-performance supercapacitors

“…9, 10 Several efforts have been devoted to modify the surface of carbon materials by doping with heteroatoms (N, [11][12][13][14] B, [15][16][17] P, 18 S 14, 19 ). These heteroatoms doping not only improves the wettablility of carbon materials but also gives an acid-base character, enhancing their capacitance by the pseudocapacitive effect.…”