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Electrodeposition of porous graphene networks on nickel foams as supercapacitor electrodes with high capacitance and remarkable cyclic stability.

Yang S, Deng B, Ge R, Zhang L, Wang H, Zhang Z, Zhu W, Wang G - Nanoscale Res Lett (2014)

Bottom Line: The electrodeposition process was accomplished by electrochemical reduction of graphene oxide (GO) in its aqueous suspension.The resultant binder-free PG/NF electrodes exhibited excellent double-layer capacitive performance with a high rate capability and a high specific capacitance of 183.2 mF cm(-2) at the current density of 1 mA cm(-2).Moreover, the specific capacitance maintains nearly 100% over 10,000 charge-discharge cycles, demonstrating a remarkable cyclic stability of these porous supercapacitor electrodes. 82.47.Uv (Electrochemical capacitors); 82.45.Fk (Electrodes electrochemistry); 81.05.Rm (Fabrication of porous materials).

View Article: PubMed Central - PubMed

Affiliation: Hefei National Laboratory for Physical Sciences at Microscale, and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China, shorlin@mail.ustc.edu.cn.

ABSTRACT

Unlabelled: We describe a facile, low-cost, and green method to fabricate porous graphene networks/nickel foam (PG/NF) electrodes by electrochemical deposition of graphene sheets on nickel foams (NFs) for the application of supercapacitor electrodes. The electrodeposition process was accomplished by electrochemical reduction of graphene oxide (GO) in its aqueous suspension. The resultant binder-free PG/NF electrodes exhibited excellent double-layer capacitive performance with a high rate capability and a high specific capacitance of 183.2 mF cm(-2) at the current density of 1 mA cm(-2). Moreover, the specific capacitance maintains nearly 100% over 10,000 charge-discharge cycles, demonstrating a remarkable cyclic stability of these porous supercapacitor electrodes.

Pacs: 82.47.Uv (Electrochemical capacitors); 82.45.Fk (Electrodes electrochemistry); 81.05.Rm (Fabrication of porous materials).

No MeSH data available.


SEM images of PG/NFs deposited under -1.2 V with different deposition times. (A) 300, (B) 400, (C) 500, (D) 600, and (E) 700 s. A(I) to E(I) are the top views, and A(II) to E(II) are the cross-sections. Scale bar: 100 μm.
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Fig2: SEM images of PG/NFs deposited under -1.2 V with different deposition times. (A) 300, (B) 400, (C) 500, (D) 600, and (E) 700 s. A(I) to E(I) are the top views, and A(II) to E(II) are the cross-sections. Scale bar: 100 μm.

Mentions: Electrodepositions of graphene sheets were firstly conducted at the potential of -1.2 V with deposition times of 300, 400, 500, 600, and 700 s. The mass of deposited graphene materials per unit area of PG/NF increased from 1.0 to 1.3, 1.5, 1.8, or 2.0 mg cm-2 as the deposition time increased from 300 to 400, 500, 600, or 700 s. Figure 2 displays the SEM images of top view and cross-section of PG/NF electrodes. Compared with bare NF shown in Additional file 1: Figure S1, the PG/NF SEM images show that the graphene materials have been deposited onto the outsides and insides of the pores of the NFs. As shown from Figure 2A(I) and A(II) to Figure 2E(I) and E(II), with the increase of deposition time, more graphene sheets were deposited onto the NF frameworks. Notably, more graphene sheets were coated on the outside of the NFs, which can be seen from the top view SEM images shown from Figure 2A(I) to E(I). For electrodeposition processes longer than 600 s, the deposited graphene sheets began to cover the pores of the NF electrodes, which would block the diffusion of electrolytes into those pores. Figure 3 shows the high magnification SEM images of the PG/NFs. Figure 3B,D is the enlarged views of the squares in Figure 3A,C, respectively. It is obvious that the deposited graphene sheets formed porous structure with pore sizes in tens of micrometers from both top view and cross-section view. In addition, crumpled morphology is also observed on the surface of the porous graphene networks (Figure 3B,D). These porous architectures and crumpled surface topography could enlarge the surface area and thus enhance the specific capacitance of the electrodes.Figure 2


Electrodeposition of porous graphene networks on nickel foams as supercapacitor electrodes with high capacitance and remarkable cyclic stability.

Yang S, Deng B, Ge R, Zhang L, Wang H, Zhang Z, Zhu W, Wang G - Nanoscale Res Lett (2014)

SEM images of PG/NFs deposited under -1.2 V with different deposition times. (A) 300, (B) 400, (C) 500, (D) 600, and (E) 700 s. A(I) to E(I) are the top views, and A(II) to E(II) are the cross-sections. Scale bar: 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493843&req=5

Fig2: SEM images of PG/NFs deposited under -1.2 V with different deposition times. (A) 300, (B) 400, (C) 500, (D) 600, and (E) 700 s. A(I) to E(I) are the top views, and A(II) to E(II) are the cross-sections. Scale bar: 100 μm.
Mentions: Electrodepositions of graphene sheets were firstly conducted at the potential of -1.2 V with deposition times of 300, 400, 500, 600, and 700 s. The mass of deposited graphene materials per unit area of PG/NF increased from 1.0 to 1.3, 1.5, 1.8, or 2.0 mg cm-2 as the deposition time increased from 300 to 400, 500, 600, or 700 s. Figure 2 displays the SEM images of top view and cross-section of PG/NF electrodes. Compared with bare NF shown in Additional file 1: Figure S1, the PG/NF SEM images show that the graphene materials have been deposited onto the outsides and insides of the pores of the NFs. As shown from Figure 2A(I) and A(II) to Figure 2E(I) and E(II), with the increase of deposition time, more graphene sheets were deposited onto the NF frameworks. Notably, more graphene sheets were coated on the outside of the NFs, which can be seen from the top view SEM images shown from Figure 2A(I) to E(I). For electrodeposition processes longer than 600 s, the deposited graphene sheets began to cover the pores of the NF electrodes, which would block the diffusion of electrolytes into those pores. Figure 3 shows the high magnification SEM images of the PG/NFs. Figure 3B,D is the enlarged views of the squares in Figure 3A,C, respectively. It is obvious that the deposited graphene sheets formed porous structure with pore sizes in tens of micrometers from both top view and cross-section view. In addition, crumpled morphology is also observed on the surface of the porous graphene networks (Figure 3B,D). These porous architectures and crumpled surface topography could enlarge the surface area and thus enhance the specific capacitance of the electrodes.Figure 2

Bottom Line: The electrodeposition process was accomplished by electrochemical reduction of graphene oxide (GO) in its aqueous suspension.The resultant binder-free PG/NF electrodes exhibited excellent double-layer capacitive performance with a high rate capability and a high specific capacitance of 183.2 mF cm(-2) at the current density of 1 mA cm(-2).Moreover, the specific capacitance maintains nearly 100% over 10,000 charge-discharge cycles, demonstrating a remarkable cyclic stability of these porous supercapacitor electrodes. 82.47.Uv (Electrochemical capacitors); 82.45.Fk (Electrodes electrochemistry); 81.05.Rm (Fabrication of porous materials).

View Article: PubMed Central - PubMed

Affiliation: Hefei National Laboratory for Physical Sciences at Microscale, and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China, shorlin@mail.ustc.edu.cn.

ABSTRACT

Unlabelled: We describe a facile, low-cost, and green method to fabricate porous graphene networks/nickel foam (PG/NF) electrodes by electrochemical deposition of graphene sheets on nickel foams (NFs) for the application of supercapacitor electrodes. The electrodeposition process was accomplished by electrochemical reduction of graphene oxide (GO) in its aqueous suspension. The resultant binder-free PG/NF electrodes exhibited excellent double-layer capacitive performance with a high rate capability and a high specific capacitance of 183.2 mF cm(-2) at the current density of 1 mA cm(-2). Moreover, the specific capacitance maintains nearly 100% over 10,000 charge-discharge cycles, demonstrating a remarkable cyclic stability of these porous supercapacitor electrodes.

Pacs: 82.47.Uv (Electrochemical capacitors); 82.45.Fk (Electrodes electrochemistry); 81.05.Rm (Fabrication of porous materials).

No MeSH data available.