Reduced graphene oxide–bismuth oxide composite as electrode material for supercapacitors

Abstract

We have reported a new reduced graphene oxidebismuth oxide composite that can be used as a supercapacitor electrode. Bi 2 O 3 was synthesized from bismuth nitrate pentahydrate and oxalic acid as a precipitating agent using a hydrothermal process in an aqueous graphene oxide suspension. Instead of mixing graphene oxide with bismuth oxide, we have developed a bismuth oxalate precipitation between the layers. As prepared, composite of hydrated bismuth oxalate and graphene oxide was converted to bismuth oxide and reduced graphene oxide by thermal decomposition in a muffle stove. The material exhibited the specific capacitance of 94 F/ g at current density 0.2 A/g. Using the cyclic voltammetry, the specific capacitance was as high as 55 F/g at scan rate 5 mV/s over the potential range 0-1 V. The material exhibited longterm cycle stability retaining 90 % specific capacitance after 3,000 cycles. Except Bi 3+ ions present in Bi 2 O 3 , some amount of higher energy Bi 5+ was confirmed.

Facile synthesis of rod-like Bi 2 O 3 nanoparticles as an electrode material for pseudocapacitors

“…When the scan rate increases to 50 mV s -1 , the specific capacitance for the Bi 2 O 3 still remains at 276 F g -1 , displaying their good rate capability. The specific capacitances reported herein are much larger than that 98 F g -1 of Bi 2 O 3 thin films [24] and 94 F g -1 of reduced graphene oxide-bismuth oxide composite material [35]. Capacitive property of the Bi 2 O 3 is also comparable to some other novel composites, for instance, activated graphene quantum dots [36] and graphene/PANI composite [37] with specific capacitances of 236 F g -1 and 448 F g -1 , respectively.…”

β‐Co(OH)2 Nanosheets: A Superior Pseudocapacitive Electrode for High‐Energy Supercapacitors

“…Ultrafast charging/discharging capability (7 s) of the cell is also realized,f or example, at ap ower density of 8kWkg À1 the cell is callable of delivering the energy density of 15.64 Wh kg À1 .T his value is one of the best figures obtained for b-Co(OH) 2 or its composite-based asymmetrica ssemblies reportede lsewhere ( Table T1 in the Supporting Information). [19,26,28,35,50] Figure 4c shows the electrochemical impedance spectroscopy (EIS) curve of the asymmetric supercapacitor in the frequencyr ange of 0.1 Hz to 100 kHz at open-circuit conditions. The plot exhibits as emicircular curve followed by al inear curve, indicating an ideal capacitiveb ehavior of the supercapacitor.…”

“…Activated carbon (AC) is ap opular choice for EDLC components, in particular,f or the power component in the asymmetric configuration owing to its fascinating characteristics such as its wide range of chemical and electrochemical stabilities, high surfacea rea, high electricalc onductivity,t ailored meso-/microporous structure, low cost, etc. [2, [10][11][12] On the other hand, there are numerousm etal oxides and hydroxides (RuO 2 , [13] MnO 2 , [14] V 2 O 5 , [15] NiO, [16][17][18][19] Mn 3 O 4 , [20] Co 3 O 4 , [21][22][23] Bi 2 O 3 , [24][25][26] and Ni(OH) 2 [27][28][29][30][31][32] )h ave been exploited as pseudoca- pacitivee lectrodes, and af ew of them have been paired with AC too. Amongt hem, hydroxide-based materials have been extensively studied to improve the energy density of supercapacitors.…”

Nanosized‐Zinc‐Mediated Self‐Gelation of Graphene Oxide under Ambient Conditions

“…Based on the high‐resolution spectra of the C 1 s in Figure , the binding energy was calibrated based on the graphite C 1 s peak (C=C) at approximately 284.8 eV . Thus, the C−C bond presented as a peak located at a binding energy of 285.4 eV . The peak at approximately 286.3 eV indicates C−OH groups from hydroxyl/carboxyl groups.…”

“…[32] Thus, the CÀCb ond presented as ap eak located at ab inding energy of 285.4 eV. [33] The peak at approximately 286.3 eV indicates CÀOH groups from hydroxyl/carboxyl groups.T he peak located at 287.5 eV indicates theC ÀOÀCe ther linkage.T he peak at approximately 288.2 eV is attributedt oC =Of rom carbonyl or carboxyl groups,a nd the peak at 289.2 eV indicates ÀCOO from carboxyl, carboxylic anhydride,a nd ester groups. [28e, 32] In GO and rGO with low degree of reduction (rGO-0.5a nd rGO-1), the carbon peaks are relatively wide and the peaks for oxygen functional groups are very strong.…”