Introducing organic metallic salts to enhance capacitive energy storage of carbon nanofibers

A suitable form of precursor carbon is a great importance for electrochemical performance of carbon materials for supercapacitor applications. Herein, we investigate the addition of organic bimetallic salts to polymer precursor for the fabrication of carbon nanofiber (CNF). The presence of additional pore structures is beneficial for transfer of electrolytes by providing more active sites and improving electrochemical performance. Compared with the samples without any metallic salts, the activated electrode shows a high specific surface area of 420 m(2) g(-1) and outstanding specific capacitance of 460 F g(-1) at 1 A g(-1). The capacitance retention shows that it retains 95.6% of initial capacitance up to 1000 cycles and 76.5% even after 9000 cycles. A high specific energy of 16 Wh kg(-1) at 250 W kg(-1) is also obtained. This strategy holds a great promise for use in energy-related applications

Synthesis and Application of a Self-Standing Zirconia-Based Carbon Nanofiber in a Supercapacitor

Electrospun metal oxide-embedded carbon nanofibers have attracted considerable attention in energy storage applications for the development and fabrication of supercapacitors owing to their unique properties such as flexibility, high capacitance, large specific surface areas, and morphological and conductivity properties. Herein, a novel zirconia-based carbon nanofiber (referred to as CNF-20ZrO(2)) was fabricated using a simple electrospinning method and applied to a supercapacitor as the electroactive material for the first time. The optimal electrode (CNF-20ZrO(2)) demonstrates a high specific capacitance of 140 F/g at 1 A/g. In addition, the assembled supercapacitor delivers maximum specific energy of 4.86 Wh/kg at a specific power of 250 W/kg and shows excellent cycling stability of 82.6% after 10 000 cycles at 1 A/g. The electrochemical performance of the electrode originates from the high content of nitrogen and oxygen species, abundant electrochemical active sites, and high ionic conductivity

CoFe Nanoparticles in Carbon Nanofibers as an Electrode for Ultra-Stable Supercapacitor

In this paper, we proposed the synthesis of CoFe nanoparticles (NPs) which have been deposited on carbon nanofibers (CNFs) with a facile electrospinning route followed by thermal reduction. The performance of obtained CNF supercapacitors are improved from 51 to 190 F/g (247 mF/cm(2)) at 0.5 A/g with the combination of CoFe NPs and graphitized carbon layers The device possessed an energy and power density of 6.6 Wh/kg and 125 W/kg, respectively. Furthermore, the capacitance retention can still maintain about 96.6% after 10,000 cycle test and it is worth noting that the cycling stability is ultrahigh. This research proves that bimetallic nanoparticles embedded in CNFs can elucidate new insights into the development new nanofiber electrode materials for the next generation of symmetric supercapacitors

Magnetic and microstructural features of Dy3+ substituted NiFe2O4 nanoparticles derived by sol-gel approach

This study explored the microstructural and magnetic features of NiFe2-xDyxO4 (x <= 0.10) NPs (nanoparticles) that were synthesized by sol-gel auto-combustion method. The single phase of spinel ferrite has been verified for all samples without any impurity. The cubic morphology of the products was also showed by SEM. Room temperature (300 K) and 10 K magnetization curves were recorded applying a dc magnetic field up to +/- 50 kOe and it was observed that magnetic features of NiFe2O4 NPs significantly changed by the substitution of Dy3+ ion. Magnetization measurements showed low order of 300 and 10 K magnetic parameters (such as K-eff, coercivity and anisotropy field values), revealing soft ferrimagnetic behaviors of all pristine and doped NiDyxFe2-xO4 (0.00 <= x <= 0.10) NPs at both 300 and 10 K. Pristine NiFe2O4 has maximum magnetic moment and saturation magnetization values among all samples. Dy3+ substitution showed a slight decrement in magnetization values compared with pristine sample. A slight increase in coercivity was noticed with Dy3+ substitution. Squareness ratios (SQRs) have a range between 0.144 and 0.324. These values are smaller than the theoretical limit of 0.50, implying the multi-domain nature for NPs. Blocking temperature (T-B) was calculated as 28 K for NiFe2O4 NPs