Synthesis of Boron‐Doped Graphene by Supercritical Fluid Processing and its Application in Symmetric Supercapacitors using Various Electrolytes

Abstract

Doping of heteroatoms on graphene networks is an efficient way of modifying both, chemical and electrochemical properties of graphene. Here, the preparation of boron doped graphene was achieved by supercritical fluid processing using sodium tetraborate as a boron source. The phase purity, structure and surface morphology of all the prepared materials were characterised by XRD, Raman spectra, FE-SEM and HR-TEM. The presence of boron bearing functionalities and type of B-doping are determined by FT-IR spectroscopy and XPS, respectively. From the different weight combination of B-source along with graphene oxide, the B-doped graphene obtained from B-source and graphene oxide are in 1 : 2 weight ratio showed an enhanced capacitive behaviour over reduced graphene oxide with an improved specific capacitance value of 270 F/g at 1 A/g and revealed a superior cycling stability of 93 % retention over 10000 cycles at 10 A/g. To appreciate the device performance, the full cell studies was performed in three different electrolytes and the energy density obtained using 1ethyl-3-methyl imidazolium tetrafluoroborate (EMIMBF 4 ) as ionic liquid electrolyte is found to be 39.3 Wh/kg which is higher than both 20 % KOH solution (5.1 Wh/kg) and 1 M TEABF 4 in acetonitrile (18.6 Wh/kg).[a] S.

Fabrication of resorcinol-based porous resin carbon material and its application in aqueous symmetric supercapacitors

“…With the carbonization temperature increasing, the intensity of the peak at around 25.6 is basically unchanged, and the peak position is not shi, while the full-width at half-maximum (FWHM) decreases. 28,29 These observations suggest an increased crystallite size, corresponding to the higher graphitized degree. A weak peak at 2q ¼ 43 is assigned to the (101) crystalline plane of carbon materials.…”

Advances and Trends in Chemically Doped Graphene

“…[ 118 ] Graphene‐based capacitors have exhibited high powder density, long durability, and flexibility. For instance, the boron monodoped system revealed a maximum specific capacitance retention of 93% through 10 000 cycles, [ 169 ] and the P/N codoped system demonstrated a capacity retention of 101% after 1000 cycles. [ 170 ] The single doping systems were further extended to include nitrogen and halogen heterodoping arrangements and even hybrid systems and in each system, the reported capacitive efficiency was higher.…”

“…Adapted with permission. [ 169 ] Copyright 2019, Wiley‐VCH. d) Nitrogen and sulfur codoped by polymerization process.…”

Effect of pore structure and doping species on charge storage mechanisms in porous carbon-based supercapacitors

“…The enhanced specific capacitance of 448 F g À1 was achieved after boron doping without adding any conductivity enhancer, which resulted from the improved conductivity of the active material by boron doping. 138 140 The above works prove that mere doping with boron can pave the way towards the design of novel supercapacitor electrodes. As aforementioned, various doping candidates including oxygen, nitrogen, phosphorus and boron have been widely introduced into the carbon matrix to improve the electrochemical performance of carbon-based supercapacitors.…”