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Nitrogen-doped, FeNi alloy nanoparticle-decorated graphene as an efficient and stable electrode for electrochemical supercapacitors in acid medium.

El-Deen AG, El-Newehy M, Kim CS, Barakat NA - Nanoscale Res Lett (2015)

Bottom Line: Compared to pristine and Ni-decorated graphene, in acid media, the introduced electrode revealed excellent specific capacitance as the corresponding specific capacitance was multiplied around ten times with capacity retention maintained at 94.9% for 1,000 cycles.Briefly, iron acetate, nickel acetate, urea, and graphene oxide were ultrasonicated and subjected to MW heating and then sintered with melanin in Ar.The introduced N-doped FeNi@Gr exhibits remarkable electrochemical behavior with long-term stability.

View Article: PubMed Central - PubMed

Affiliation: Bionanosystem Engineering Department, Chonbuk National University, Jeonju, 561-756 Republic of Korea.

ABSTRACT
Nitrogen-doped graphene decorated by iron-nickel alloy is introduced as a promising electrode material for supercapacitors. Compared to pristine and Ni-decorated graphene, in acid media, the introduced electrode revealed excellent specific capacitance as the corresponding specific capacitance was multiplied around ten times with capacity retention maintained at 94.9% for 1,000 cycles. Briefly, iron acetate, nickel acetate, urea, and graphene oxide were ultrasonicated and subjected to MW heating and then sintered with melanin in Ar. The introduced N-doped FeNi@Gr exhibits remarkable electrochemical behavior with long-term stability.

No MeSH data available.


Specific capacitance, cycling stability, and Nyquist plots. Specific capacitance for the fabricated materials at different sweep rates (a); cycling stability plots at 50 mV s − 1 (b), and Nyquist plots of N-doped FeNi@Gr, N-doped Ni@Gr, and pristine graphene electrodes in 1 M H2SO4 aqueous solution at different sweep rates (c).
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Fig4: Specific capacitance, cycling stability, and Nyquist plots. Specific capacitance for the fabricated materials at different sweep rates (a); cycling stability plots at 50 mV s − 1 (b), and Nyquist plots of N-doped FeNi@Gr, N-doped Ni@Gr, and pristine graphene electrodes in 1 M H2SO4 aqueous solution at different sweep rates (c).

Mentions: where Csp is the specific capacitance (F g−1), I is the response current (A), V is the potential (V), υ is the potential scan rate (V s−1), and m is the mass of the electroactive materials in the electrodes (g). As shown in Figure 4a, the bimetallic alloy structure achieved exceptional specific capacitance compared to the reported metal- and metal oxide-decorated graphene as the corresponding specific capacitance at 5 mV s−1 is 254 F g−1 which is about tenfolds of the other formulations. As the introduced material is based on pristine metals and the electrochemical property investigations have been carried out in acidic media, cycling performance is important to check the corrosion resistance of the introduced alloy NPs. A long-term cycle stability test was evaluated for 1,000 cycles (Figure 4b). It can be clearly claimed that the introduced electrode exhibited lossless performance in specific capacitance as after 1,000 cycles (the analysis time was more than 11 h), the specific capacitance maintained at 96.4% from the original value. This finding indicates excellent capacity retention and better long-term cycling stability. EIS confirmed the fast ion transport within the introduced N-doped FeNi@Gr electrode, as shown in Figure 4c. As shown, Nyquist plots demonstrate that the introduced modified graphene at the high-frequency region has the nearest intersecting point on the real axis that represents equivalent series resistance (ESR), indicating that the N-doped FeNi@Gr electrode has low combination resistance of ionic resistance of the electrolyte, intrinsic resistance of the active materials, and small contact resistance between the active material and the current collector compared to other formulations [39]. This difference is attributed to the higher reactivity and faster reaction kinetics and electrode conductivity. The interesting finding is that the intercalating of FeNi alloy into the graphene composite leads to improvement in the conductivity which contributed to pseudocapacitance. Moreover, the smallest semicircle in the high frequency range indicates the FeNi@Gr electrode has a much lower charge transfer resistance and ion diffusion resistance [40,41].Figure 4


Nitrogen-doped, FeNi alloy nanoparticle-decorated graphene as an efficient and stable electrode for electrochemical supercapacitors in acid medium.

El-Deen AG, El-Newehy M, Kim CS, Barakat NA - Nanoscale Res Lett (2015)

Specific capacitance, cycling stability, and Nyquist plots. Specific capacitance for the fabricated materials at different sweep rates (a); cycling stability plots at 50 mV s − 1 (b), and Nyquist plots of N-doped FeNi@Gr, N-doped Ni@Gr, and pristine graphene electrodes in 1 M H2SO4 aqueous solution at different sweep rates (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385200&req=5

Fig4: Specific capacitance, cycling stability, and Nyquist plots. Specific capacitance for the fabricated materials at different sweep rates (a); cycling stability plots at 50 mV s − 1 (b), and Nyquist plots of N-doped FeNi@Gr, N-doped Ni@Gr, and pristine graphene electrodes in 1 M H2SO4 aqueous solution at different sweep rates (c).
Mentions: where Csp is the specific capacitance (F g−1), I is the response current (A), V is the potential (V), υ is the potential scan rate (V s−1), and m is the mass of the electroactive materials in the electrodes (g). As shown in Figure 4a, the bimetallic alloy structure achieved exceptional specific capacitance compared to the reported metal- and metal oxide-decorated graphene as the corresponding specific capacitance at 5 mV s−1 is 254 F g−1 which is about tenfolds of the other formulations. As the introduced material is based on pristine metals and the electrochemical property investigations have been carried out in acidic media, cycling performance is important to check the corrosion resistance of the introduced alloy NPs. A long-term cycle stability test was evaluated for 1,000 cycles (Figure 4b). It can be clearly claimed that the introduced electrode exhibited lossless performance in specific capacitance as after 1,000 cycles (the analysis time was more than 11 h), the specific capacitance maintained at 96.4% from the original value. This finding indicates excellent capacity retention and better long-term cycling stability. EIS confirmed the fast ion transport within the introduced N-doped FeNi@Gr electrode, as shown in Figure 4c. As shown, Nyquist plots demonstrate that the introduced modified graphene at the high-frequency region has the nearest intersecting point on the real axis that represents equivalent series resistance (ESR), indicating that the N-doped FeNi@Gr electrode has low combination resistance of ionic resistance of the electrolyte, intrinsic resistance of the active materials, and small contact resistance between the active material and the current collector compared to other formulations [39]. This difference is attributed to the higher reactivity and faster reaction kinetics and electrode conductivity. The interesting finding is that the intercalating of FeNi alloy into the graphene composite leads to improvement in the conductivity which contributed to pseudocapacitance. Moreover, the smallest semicircle in the high frequency range indicates the FeNi@Gr electrode has a much lower charge transfer resistance and ion diffusion resistance [40,41].Figure 4

Bottom Line: Compared to pristine and Ni-decorated graphene, in acid media, the introduced electrode revealed excellent specific capacitance as the corresponding specific capacitance was multiplied around ten times with capacity retention maintained at 94.9% for 1,000 cycles.Briefly, iron acetate, nickel acetate, urea, and graphene oxide were ultrasonicated and subjected to MW heating and then sintered with melanin in Ar.The introduced N-doped FeNi@Gr exhibits remarkable electrochemical behavior with long-term stability.

View Article: PubMed Central - PubMed

Affiliation: Bionanosystem Engineering Department, Chonbuk National University, Jeonju, 561-756 Republic of Korea.

ABSTRACT
Nitrogen-doped graphene decorated by iron-nickel alloy is introduced as a promising electrode material for supercapacitors. Compared to pristine and Ni-decorated graphene, in acid media, the introduced electrode revealed excellent specific capacitance as the corresponding specific capacitance was multiplied around ten times with capacity retention maintained at 94.9% for 1,000 cycles. Briefly, iron acetate, nickel acetate, urea, and graphene oxide were ultrasonicated and subjected to MW heating and then sintered with melanin in Ar. The introduced N-doped FeNi@Gr exhibits remarkable electrochemical behavior with long-term stability.

No MeSH data available.