Limits...
Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel.

Gund GS, Dubal DP, Chodankar NR, Cho JY, Gomez-Romero P, Park C, Lokhande CD - Sci Rep (2015)

Bottom Line: The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles).Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility.Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

View Article: PubMed Central - PubMed

Affiliation: 1] Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur, - 416004 (M.S), India [2] Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea [3] Catalan Institute of Nanoscience and Nanotechnology, CIN2, ICN2 (CSIC-ICN), Campus UAB, E-08193 Bellaterra (Barcelona), Spain.

ABSTRACT
The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility. Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

No MeSH data available.


(a) CV curves and (b) specific capacitance at different scan rates, (c) GCD profile and (d) specific capacitance at various current densities, (e) capacitive retention as a function of cycle number; inset is the CV curves at different CV cycles and (f) Nyquist plot of MnO2/MnO2 symmetric FSS-SC device.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4513645&req=5

f5: (a) CV curves and (b) specific capacitance at different scan rates, (c) GCD profile and (d) specific capacitance at various current densities, (e) capacitive retention as a function of cycle number; inset is the CV curves at different CV cycles and (f) Nyquist plot of MnO2/MnO2 symmetric FSS-SC device.

Mentions: The CV measurements of symmetric FSS-SC device (MnO2/MnO2) were carried out between 0 to +1 V at various scan rates; see Fig. 5(a). The specific capacitances of the device were evaluated in accordance with the CV examinations at different scan rates, and are plotted in Fig. 5(b). The maximum specific capacitance of 85 F g−1 was obtained at a scan rate of 5 mV s−1. As it could be expected, the specific capacitance diminishes gradually with increasing scan rate but only to a minor extent. The excellent capacitive behavior with the exceptional reversibility of symmetric FSS-SC device clearly reflects from the mirror-image of current response on reverse voltage in CV profile. Additionally, the galvanostatic charge–discharge (GCD) technique is a direct tool to examine the applicability of fabricated SC device, since this technique can easily evaluate the rate capability of a device by judging the rate of change of voltage with time during charging and discharging at various current densities within a stable potential window. The GCD curves of the symmetric FSS-SC device at different current densities are plotted, as a potential−time profile, in Fig. 5(c). The estimated values of specific capacitance at different current densities are plotted in Fig. 5(d), and show a maximum capacitance of 91 F g−1 at a current density of 0.69 A g−1. The observed difference in specific capacitances evaluated through GCD and CV measurement can be easily explained. Thus, the estimated specific capacitance through CV measurement is at a particular voltage, whereas GCD measurement furnishes an average capacitance over the voltage range of 0–1  V4344. Furthermore, the long cycling (for 3000 CV cycles at 100 mV s−1 of scan rate) and electrochemical impendence measurements (with 10 mV of AC amplitude and within the frequency range of 100 mHz to 100 kHz) have verified the excellent cycling stability (83% of capacitive retention, see Fig. 5(e)) and ion transports (Rs = 0.3 Ω cm−2 and Rct = 9.51 Ω cm−2, see the Fig. 5(f)) of fabricated symmetric FSS-SC device, respectively.


Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel.

Gund GS, Dubal DP, Chodankar NR, Cho JY, Gomez-Romero P, Park C, Lokhande CD - Sci Rep (2015)

(a) CV curves and (b) specific capacitance at different scan rates, (c) GCD profile and (d) specific capacitance at various current densities, (e) capacitive retention as a function of cycle number; inset is the CV curves at different CV cycles and (f) Nyquist plot of MnO2/MnO2 symmetric FSS-SC device.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4513645&req=5

f5: (a) CV curves and (b) specific capacitance at different scan rates, (c) GCD profile and (d) specific capacitance at various current densities, (e) capacitive retention as a function of cycle number; inset is the CV curves at different CV cycles and (f) Nyquist plot of MnO2/MnO2 symmetric FSS-SC device.
Mentions: The CV measurements of symmetric FSS-SC device (MnO2/MnO2) were carried out between 0 to +1 V at various scan rates; see Fig. 5(a). The specific capacitances of the device were evaluated in accordance with the CV examinations at different scan rates, and are plotted in Fig. 5(b). The maximum specific capacitance of 85 F g−1 was obtained at a scan rate of 5 mV s−1. As it could be expected, the specific capacitance diminishes gradually with increasing scan rate but only to a minor extent. The excellent capacitive behavior with the exceptional reversibility of symmetric FSS-SC device clearly reflects from the mirror-image of current response on reverse voltage in CV profile. Additionally, the galvanostatic charge–discharge (GCD) technique is a direct tool to examine the applicability of fabricated SC device, since this technique can easily evaluate the rate capability of a device by judging the rate of change of voltage with time during charging and discharging at various current densities within a stable potential window. The GCD curves of the symmetric FSS-SC device at different current densities are plotted, as a potential−time profile, in Fig. 5(c). The estimated values of specific capacitance at different current densities are plotted in Fig. 5(d), and show a maximum capacitance of 91 F g−1 at a current density of 0.69 A g−1. The observed difference in specific capacitances evaluated through GCD and CV measurement can be easily explained. Thus, the estimated specific capacitance through CV measurement is at a particular voltage, whereas GCD measurement furnishes an average capacitance over the voltage range of 0–1  V4344. Furthermore, the long cycling (for 3000 CV cycles at 100 mV s−1 of scan rate) and electrochemical impendence measurements (with 10 mV of AC amplitude and within the frequency range of 100 mHz to 100 kHz) have verified the excellent cycling stability (83% of capacitive retention, see Fig. 5(e)) and ion transports (Rs = 0.3 Ω cm−2 and Rct = 9.51 Ω cm−2, see the Fig. 5(f)) of fabricated symmetric FSS-SC device, respectively.

Bottom Line: The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles).Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility.Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

View Article: PubMed Central - PubMed

Affiliation: 1] Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur, - 416004 (M.S), India [2] Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea [3] Catalan Institute of Nanoscience and Nanotechnology, CIN2, ICN2 (CSIC-ICN), Campus UAB, E-08193 Bellaterra (Barcelona), Spain.

ABSTRACT
The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility. Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

No MeSH data available.