Incorporation of Manganese Dioxide within ... - ACS Publications

Dual electronic-ionic conductivity of pseudo-capacitive filler enables high volumetric .... Ultrahigh volumetric performance of a free-standing compac...
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Incorporation of Manganese Dioxide within Ultraporous Activated Graphene for High-Performance Electrochemical Capacitors Xin Zhao†,‡, Lili Zhang†, Shanthi Murali†, Meryl D Stoller, †, Qinghua Zhang‡, Yanwu Zhu,*,§ and Rodney S. Ruoff*,†



Department of Mechanical Engineering and the Materials Science and Engineering Program,

The University of Texas at Austin, One University Station C2200, Austin, TX 78712, ‡

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College

of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China, §

Department of Materials Science and Engineering, University of Science and Technology of

China, Hefei, 230036, P. R. China. Email: [email protected], [email protected]

0.5

(a) o

M nO 2 Loading

Deriv. Weight (%/ C)

0.4 0.3 0.2 0.1

(b)

AGMn-5min AGMn-10min AGMn-30min AGMn-60min AGMn-90min AGMn-120min

0.0 0

40 80 Reation Time (min)

120

200

400 600 Temperature (°C)

800

Figure S1. (a) MnO2 mass uptake plotted as a function of reaction time, (b) DTG curves AGMn composites with different reaction times.

(a)

Mn 2p3/2

Intensity (a.u.)

O 2s

1000

C 2s

Mn 3s

800

600 400 200 Binding Energy (eV)

0

Intensity (a.u.)

Mn 2p

660

(b)

Mn 2p1/2

655

650 645 640 Binding Energy (eV)

635

Figure S2. (a) XPS survey spectrum of AGMn-10min, indicating the presence of Mn and O as well as C elements in composites, (b) Mn spectrum for AGMn-10min.

Figure S3. (a) High resolution SEM image of AGMn-120min nanocomposites, (b) BF-STEM image of the same area as (a), (c) SEM image combined with EDS mapping in the same area and relative intensities of C (red), Mn (green) and O (blue) elements.

Figure S4. Transmission electron micrographs for AGMn-10min-h with different magnifications

20 0

-20 10mV/s 50mV/s 100mV/s 200mV/s

-40

0.0

0.2

0.4

0.6

Potential (V)

0.8

(b)

AGMn-120min 1.0

Potential (V)

Current Density (A/g)

(a)

AGMn-120min

40

1A/g (220F/g) 2A/g (212F/g) 5A/g (198F/g) 10A/g(192F/g)

0.8 0.6 0.4 0.2 0.0

1.0

0

50

Time (s)

100

Figure S5. (a) Cyclic voltammograms and(b) charge-discharge curves with different rates for AGMn-120min composites.

1.2V 1.4V 1.6V 1.8V 2.0V

8

4

20

(a)

20mV/s

Current Density (A/g)

Current Density (A/g)

12

0

-4

(b)

20mV/s 1.0V 1.2V 1.4V

15 10 5 0 -5

1M H2SO4

-10

0.0

0.5

1.0

Voltage (V)

1.5

2.0

0.0

0.5

1.0

1.5

Voltage (V)

Figure S6. (a) CV curves of an optimized AGMn// aMEGO asymmetric supercapacitor measured at different potential windows in 1M Na2SO4 aqueous solution (b) and 1M H2SO4 aqueous solution at a scan rate of 20 mV/s.