Freestanding flexible graphene foams@polypyrrole@MnO₂ electrodes for high-performance supercapacitors

Abstract

A new composite electrode design was successfully fabricated based on 3D flexible graphene foams (GF) with interconnected macropores as the freestanding substrate and a composite of MnO2 nanoparticles and polypyrrole (PPy) as an integrated electrode.

Flexible and Wearable All‐Solid‐State Supercapacitors with Ultrahigh Energy Density Based on a Carbon Fiber Fabric Electrode

“…However, the poresize distributions are similar. [36][37][38] After oxidation treatment, the intensity ratio I G /I D increases from 0.99 for CC to 1.04 for 3-CC, indicating an increase in the average size of the sp 2 domain on the surface of 3-CC and a decrease in the degree of disorder. [35] Thus, the same pore-size distribution tested by BJH analysis may not indicate the true situation of the pore-size distributions of our pristine and treated sample.…”

Freestanding Gold/Graphene‐Oxide/Manganese Oxide Microsupercapacitor Displaying High Areal Energy Density

“…Figure B presents the GCD curves for current densities from 1.5 to 25 mA cm −2 recorded for the symmetric device outlined in Figure A i. The near linearity and symmetrical appearance of the curves indicate that the solid‐state device exhibits a near‐ideal supercapacitor behavior . Notably, the inset in Figure B reveals a voltage drop ( IR drop) of 25 mV at a current density of 1.5 mA cm −2 , indicating an overall device resistance of 16.7 Ω cm −2 .…”

“…Galvanostatic charge/discharge (GCD) curves were recorded to characterize the electrode response at constant currents (Figure E). The almost linear and symmetrical appearances of the GCD curves at current densities ranging from 5 to 25 mA cm −2 indicate that the electrode facilitates reversible redox reactions and its performance is close to ideal supercapacitance . In particular, the high capacitance was retained even at a high current density of 25 mA cm −2 , exhibiting a long (58 s) discharge time (Figure E).…”

“…The almostl inear ands ymmetrical appearances of the GCD curves at currentd ensities ranging from 5t o2 5mAcm À2 indicate that the electrode facilitates reversible redox reactions and its performance is closet oi deal supercapacitance. [49,50] In particular, the high capacitance was retained even at ah igh current density of 25 mA cm À2 ,e xhibiting al ong (58 s) discharget ime (Figure 2E). The specific areal capacitance calculated from the GCD curves is presented in Figure 2F,f urther displaying the excellent capacitance properties of the electrode even at high current densities.…”

电化学离子交换法辅助制备可用作高性能超级电容器电极的Co3O4/NiCo2O4纳米复合材料

“…Despite these advantages, its relatively low energy density must be increased to satisfy their practical applications. Compared with conventional carbon materials featured with high conductivity and low electric double layer capacitance [1, [7][8][9], the transition metal oxides/hydroxides (such as RuO 2 , Co 3 O 4 , NiO, MnO 2 and Ni(OH) 2 ) present high pseudocapacitance through redox reactions taking place at the interface of electrode/electrolyte, which can enhance the energy density of device [10][11][12][13][14]. Among these electroactive materials, Co 3 O 4 has dominated over other materials due to its low cost, simple synthetic process and extremely high theoretical capacitance (~3560 F g -1 ) [15,16].…”