Supporting Information

Konjak Sponge Derived Carbon Flakes with Optimized Pore Structure for High Performance Supercapacitor

Bing Han1*, Chongchong Geng1, Gong Cheng1

1 College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, P. R. China

Correspondence should be addressed to Bing. Han; hanbing01@ncepu.edu.cn

Fig. S1. TEM images of UAC samples under different magnifications.

Fig. S2. Transmission electron microscopy (TEM) images of (a and d) KAC-1, (b and e) KAC-2 and (c and f) KAC-4.

Fig. S3. Transmission electron microscopy (TEM) images of (a) KAC-700, (b) KAC-800 and (c) KAC-900, with the related digital micrograph showing the lateral distance information, the numbers demonstrated the lateral distance in the selected area, scale bar = 10 nm.

Fig. S4. TEM images of (a) KAC-1, (b) KAC-2 and (c) KAC-4, with the related digital micrograph showing the lateral distance information, the numbers demonstrated the lateral distance in the selected area, scale bar = 10 nm.

Fig S5. Selected-area electron diffraction pattern of (a) KAC-700 and (b) KAC-4.

Fig. S6. O1s spectra of KAC based samples.

Table S1. Elemental analysis results (atomic%) based XPS data.Sample Elemental Analysis (at.%)

C O N

KAC-700 88.2 11.1 0.7KAC-800 91.4 8.6 --KAC-900 95.9 4.1 --KAC-1 94.8 4.7 0.5KAC-2 95.3 4.7 --KAC-4 97.3 2.7 --

Fig. S7. CV curves of KAC based materials under scan rates of 1 mV/s, 5 mV/s, 10 mV/s, 20 mV/s, 50 mV/s, 100 mV/s.

Fig. S8. GCD curves of KAC based materials under the current densities of 0.5 A/g, 1 A/g, 2 A/g, 5 A/g, 8 A/g and 10 A/g.

Fig. S9. GCD curves (a) and the calculated specific capacitance (b) of UAC sample under different current densities.

Fig. S10. The microporous specific surface area (SSAmic) based on DFT model (Left Y axis), the microporous volume and ratio between mesoporous and microporous volume (Vmes/Vmic) (Right Y axis) of KAC based samples.

Table S2. The specific capacitance calculated from the discharging curves of KAC based samples and the capacitance retention under 10 A/g compared with that of 0.5 A/g.

Sample

Specific capacitance (F/g)Capacitance

RetentionCurrent Density (A/g)

0.5 1 2 5 8 10

KAC-700 235.1 209.3 189.7 173.0 165.3 164.5 70%

KAC-800 223.0 200.6 182.9 170.3 163.7 157.1 70%

KAC-900 161.8 150.6 140.1 133.6 127.3 125.3 77%

KAC-1 209.4 186.3 171.2 158.3 153.2 152.0 72%

KAC-2 227.0 203.0 188.0 174.9 167.2 161.8 71%

KAC-4 200.1 185.4 171. 8 163.7 155.5 154.0 77%

Table S3. Specific capacitance of KAC based matetials using three-electrode

cells reported in literatures.

Method Precursor Electrolyte

Specificcapacitan

ce(F/g)

Current density Ref.

KOH activation Konjak sponge 1 M H2SO4 235 0.5 A/g This work

KOH activation Cotton stalk 1 M H2SO4 254 0.2 A/g Ref.[1]

Hydrothermal carbonization and KOH activation

Corn straw 6 M KOH 222 1 A/g Ref.[2]

ZnCl2 activationPotato waste

residue2 M KOH 255 0.5 A/g Ref. [3]

K2FeO4 activation Bamboo char 6 M KOH 222 0.5A/g Ref.[4]

Glutaraldehyde-cross-linking and K2CO3 activation

Chitosan 3 M KOH 246 0.5 A/g Ref.[5]

Salt sealing and pyrolysisSalvia splendens

petals1 M Na2SO4 221 1 A/g Ref.[6]

KOH+CO2 activation Cassava peel waste 1 M H2SO4 153 0.25 A/g Ref.[7]

KOH templating and activation Lignin 1 M H2SO4 165 0.05 A/g Ref. [8]

Hard template strategy and KOH activation

Soybean 6 M KOH 243 0.5 A/g Ref.[9]

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