1

Supporting Information

Cation-anion Double Hydrolysis Derived Layered Single

Metal Hydroxide Superstructure for Boosted

Supercapacitive Energy Storage

C. D. Gu1, X. Ge, X.L. Wang, J.P. Tu

State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and

Applications for Batteries of Zhejiang Province and School of Materials Science and

Engineering, Zhejiang University, Hangzhou 310027, China.

Figure S1-S5: SEM, TEM, FTIR and XPS results of α-Ni(OH)2 synthesized at different

conditions.

Figure S6-S7: XRD, SEM and TEM results of α-Co(OH)2 synthesized at different conditions

Figure S8: The pH value of the aqueous solution of NaNCO. (b) UV-Vis spectra of aqueous solution containing only metal ions (Ni2+ or Co2+) or mixed with NCO-.Figure S9: Schematic illustration of the assembly process of LSHs and related discussion.Figure S10-S11: FTIR, XPS and electrochemical characterizations of α-Co(OH)2 synthesized

at different conditions.

Figure S12: Electrochemical behavior of the actived carbon and high-loading hybrid

capacitor.

Table S1: Comparison of literatures reporting powder-based Ni(OH)2 used in supercapacitor.

Table S2: Comparison of literatures reporting powder-based Co(OH)2 used in supercapacitor.

1 Corresponding AuthorTel./fax.: +86 571 87952573 E-mail addresses: cdgu@zju.edu.cn (C. D. Gu)

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2015

2

Figure S1 Time dependent experiment showing the growth process of 3D-ICHA α-Ni(OH)2.

3

Figure S2 More SEM images of SOS α-Ni(OH)2. The non-uniform nature of the lateral size

of the sheet in the substrate can be observed.

4

Figure S3 A weakly connected region of 3D-ICHA α-Ni(OH)2 is torn apart by electron beam

radiation, while the building blocks weren’t torn apart.

5

Figure S4 Influence of pumping method and concentration on the assembly behavior of α-

Ni(OH)2. In (a) and (b) Ni2+ was pumped into NCO-, while the concentration is different (a:

0.1 M Ni-0.1 NCO, b: 0.1 M Ni-1 NCO). In (c-e) NCO- was pumped into Ni2+ (c: 0.1 NCO-

0.1 Ni , d: 1 NCO-0.1 Ni, e: 0.1 NCO-1 Ni). We highlight the existance of sheet-on-rod α-

Ni(OH)2 with elliptic red marks.

6

3500 3000 2500 2000 1500 1000 500

(B) 0.05 NCO-0.015 Ni

Tra

nsm

ittan

ce (%

) Wavenumber (cm-1)

(a)

(A) 0.015 Ni-0.05 NCO

3640 (O-H)

3434 (N-H)

2256, 2223 (N=C=O)

1630(H-O-H)

628(Ni-O)

1200 1000 800 600 400 200 0

Inten

sity

(CPS

)

Binding energy (eV)

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni

Ni 2p

O 1s

N 1s C 1s Cl 2p

Full spectra survey(b)

870 865 860 855 850

Inten

sity

(CPS

)

Binding energy (eV)

Ni 2p3/2

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni

855.5857.0860.8863.0

863.1 860.6 857.1855.4

(c)

290 288 286 284 282

288.6287.5

Inten

sity

(CPS

)

Binding energy (eV)

C 1s

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni

284.7285.9287.6288.6

285.7 284.6

(d)

536 534 532 530 528

Inten

sity

(CPS

)

Binding energy (eV)

O 1s

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni

530.6531.4

532.3

533.1

532.9

532.1 531.1530.4

(e)

401 400 399 398 397 396

Inten

sity

(CPS

)

Binding energy (eV)

N 1s

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni

398.3

398.1(f)

210 205 200 195 190

Inten

sity

(CPS

)

Binding energy (eV)

Cl 2p

(A) 0.015 Ni-0.05 NCO

(B) 0.05 NCO-0.015 Ni(g)

Figure S5 FTIR (a) and XPS (b-g) spectra of 3D-ICHA α-Ni(OH)2 and SOS α-Ni(OH)2.

7

(B) 1 NCO- 0.1 Co

Inte

nsity

(a.u

.)

(A) 0.1 Co- 1 NCO

(003) (006) (101)(012)(015) (00 12) (110)(113) (116)

12.2o (7.2 A)

10 20 30 40 50 60 70 80

2-Theta (Degree)

R-3m (166) a=b=3.14 c=21.6

Figure S6 XRD patterns of (A) 0.1 Co- 1 NCO and (B) 0.1 NCO- 1 Co.

8

Figure S7 SEM images of (a) 0.015 Co-0.05 NCO sampled without drying, (b) 0.015 Co-0.05

NCO sampled after drying and redispered in ethonal, (c) 0.1 Co- 1 NCO and (d) 1 NCO- 0.1

Co.

9

0.0 0.2 0.4 0.6 0.8 1.0

9.6

9.8

10.0

10.2

10.4

(1.00, 10.23)

(0.50, 10.36)

(0.20, 10.39)(0.10, 10.40)

(0.05, 10.30)

(0.02, 10.08)

PH

Concentration of NaNCO / mol L-1

(0.01, 9.82)

(a)

200 400 600 800 1000 1200

0.00

0.05

0.10

200 400 600 800 1000 1200

0.00

0.05

0.10

0.15

0.0075 M NiCl2 + 0.025 M NaNCO

Abso

rban

ce

Wavelength / nm

0.0075 M NiCl2

283 nm

0.0075 M CoCl2 + 0.025 M NaNCO

Abso

rban

ce

Wavelength / nm

0.0075 M CoCl2

(b)

284 nm

Figure S8 (a) The pH value of the aqueous solution of NaNCO with different concentrations. (b) UV-Vis spectra of aqueous solution containing bare metal ions

(Ni2+ or Co2+) or metal ions mixed with NCO-.

10

Figure S9 (a) shows the main interaction modes (edge-to-edge detoned as ETE and edge-to-face denoted as ETF) of small growth units (SM) and large growth units (LU).

(b) shows the formation process of 3D-ICHA α-Ni(OH)2 and SOS α-Ni(OH)2.

11

Double hydrolysis mechanism for the assembly of LSHs.

The aqueous solution of NaNCO with concentrations ranging from 0.01-1 M has a narrow pH value distribution within 9.8-10.4, which is favorable for the formation of Ni(OH)2 or Co(OH)2. Meanwhile, the precipitation of α-phase metal hydroxides should be attributed to the formation of Ni4(OH)4

4+ or Co4(OH)44+ tetramers and

further condensation based on minimal structural change.1 Ni4(OH)44+ or Co4(OH)4

4+ is supposed to serve as the basic growth unit in solution to grow 2D α-type metal hydroxides as building blocks for a series of anisotropic assembly structures.2 Moreover, the hydrolysis reaction kinetics should be highly dependent on the mixing modes of NaNCO and metal ions, which will determine the morphologies of products (see Figure 3, Figure 6, Figure S1-S4 and Figure S7).

We first define two kinds of 2D building blocks as small unit (SU) and large unit (LU).2 The SU can not nucleate out from the solution but could adhere to existing crystal nuclei, which is also named as “pre-nucleation” clusters in some literatures.3-5 The LU can directly precipitate out from the solution. Those developed micrometer sheets are also categorized as LU. One main difference between SU and LU during interaction is that SU is more likely to reorganize its structure after being attached to another growth unit. For this protocol, we can simply consider the competing edge-to-edge (ETE) and edge-to-face (ETF) interactions of 2D building blocks. The ETE and ETF interactions are also widely noticed to determine the assembly process of other 2D growth unites.6, 7 As shown in Figure S9a, there should be four kinds of basic assembly behavior: ETF between LU and LU, ETF between LU and SU, ETE between LU and LU, ETE between LU and SU. As a representative example, the formation process of 3D-ICHA α-Ni(OH)2 and SOS α-Ni(OH)2 is shown in Figure S9b. With a higher reaction kinetics (i.e., metal ion solution is introduced into NaNCO solution), nucleation is fast and large amount of hydroxides would precipitate, interact and assemble. The instant depletion of Ni2+ would leave few SU to form, thus hindering the growth of LU through mode (III). The obtained α-Ni(OH)2 has a relatively smaller size and lower crystallinity as indicated above. Large amounts of LU would directly interact through mode (II) and (IV) to form clusters. Due to higher reaction kinetics and fast assembly process, these clusters are ready to twist with each other and form 3D-ICHA structures (Figure 3a and 3c). On the other hand, when aqueous solution of NaNCO is gradually added into Ni2+ solution which delivers

12

lower hydrolysis reaction kinetics, the kinetics would gradually increase until nucleation. Once nucleation happens, the kinetics immediately decreases due to the consumption of nutrients. Then the kinetics would be kept at a stage where the formation of SU is dominated and the SU has enough time to reorganize. When the SU interact with initially precipitated LU in mode (III), the LU could grow into larger LU. On the surface of the larger LU, further precipitation and organization of SU in mode (I) would lead to the formation of SOS structure (Figure 3b and 3d). The formation process of the α-Co(OH)2 nanostructures shown in this work can also be understood according to the proposed assembly mechanism.

13

3500 3000 2500 2000 1500 1000 500

(B) 0.05 NCO-0.015 Co

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

(a)

(A) 0.015 Co-0.05 NCO

3640 (O-H)

3434 (N-H)

2223, 2256 (N=C=O)

1630(H-O-H)

637(Co-O)

1200 1000 800 600 400 200 0

Inten

sity

(CPS

)

Binding energy (eV)

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co

Co 2p

O 1s

N 1s C 1s Cl 2p

Full spectra survey(b)

792 790 788 786 784 782 780 778 776

Inten

sity

(CPS

)

Binding energy (eV)

Co 2p3/2

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co

780.4

781.9784.1786.8

785.1787.6782.3 780.6

(c)

290 288 286 284 282

Inten

sity

(CPS

)

Binding energy (eV)

C 1s

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co

284.5285.6287.6288.5

287.4288.2 286.1 284.4

(d)

536 534 532 530 528

Inten

sity

(CPS

)

Binding energy (eV)

O 1s

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co

530.6

531.4

532.3533.1

531.7532.6530.9

530.1

(e)

401 400 399 398 397 396

Inten

sity

(CPS

)

Binding energy (eV)

N 1s

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co

398.2

398.0

(f)

210 205 200 195 190

Inten

sity

(CPS

)

Binding energy (eV)

Cl 2p

(A) 0.015 Co-0.05 NCO

(B) 0.05 NCO-0.015 Co(g)

Figure S10 FTIR (a) and XPS (b-g) of 0.015 Co- 0.05 NCO and 0.015 Co- 0.05 NCO.

14

0.0 0.1 0.2 0.3 0.4 0.5 0.6

-40

-20

0

20

40

60

80

5 mV s-1

50 mV s-1

10 mV s-1Cu

rrent

den

sity

/ A g

-1

Potential vs. (Hg/HgO) / V

20 mV s-10.508 V

0.345 V

(a)

0. 193 V

0.122 V

0.0 0.1 0.2 0.3 0.4 0.5 0.6

-40

-20

0

20

40

60

80

5 mV s-1

50 mV s-1

10 mV s-1

Curre

nt d

ensit

y / A

g-1

Potential vs. (Hg/HgO) / V

20 mV s-1

0.485 V

0.348 V

(b)

0. 201 V

0.095 V

0 200 400 600

0.0

0.1

0.2

0.3

0.4

0.5

0.6

10 A g-1

43.2 s20 A g-1

18.0 s

5 A g-1

97.3 s2 A g-1

276.9 sPoten

tial v

s. (H

g/Hg

O) /

V

Time /s

1 A g-1

578.0 s

(c)

0 100 200 300 400

0.0

0.1

0.2

0.3

0.4

0.5

0.6

10 A g-1

30.5 s20 A g-1

13.2 s

5 A g-1

67.8 s2 A g-1

198.0 sPoten

tial v

s. (H

g/Hg

O) /

V

Time /s

1 A g-1

405.4 s

(d)

Figure S11 (a and c) show the CV and choronopotentiometry curves of LP α-Co(OH)2; (b

and d) show the CV and choronopotentiometry curves of WDS α-Co(OH)2.

15

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-30

-20

-10

0

10

20

30

40

Curre

nt d

ensit

y / A

g-1

Potential vs. (Hg/HgO) / V

3D-ICHA -Ni(OH)2

Active carbon

10 mV s-1(a)

0 50 100 150 200-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

Poten

tial v

s. (H

g/Hg

O) /

V

Time /s

1 A g-1 for active carbon

IR drop

0.13 V to -1.0 V115.6 s

(b)

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

-0.2

0.0

0.2

0.4

Curre

nt d

ensit

y / A

g-1

Potential vs. (Hg/HgO) / V

5 mV10 mV20 mV50 mV100 mV

1.55 V0.8 V

(c)

0 50 100 150 200 250 300 350 4000.0

0.5

1.0

1.5

mactive carbon = 57.688 mg200 mA (20.80) A g-1)12.2 s

100 mA (10.40) A g-1)27.6 s

50 mA (5.20) A g-1)64.6 s

Poten

tial v

s. (H

g/Hg

O) /

V

Time / s

10 mA (1.04 A g-1)383.8 s

20 mA (2.08 A g-1)170.7 sm3D-ICHA -Ni(OH)2 = 9.624 mg

IR drop(d)

Linear range

0 1 2 3 4 51.1

1.2

1.3

1.4

1.5

1.6

Pote

ntia

l vs.

(Hg/

HgO)

/ V

Time /s

0 50 100 150 200 250

30

35

40

45

50

Spec

ific c

apac

itanc

e / F

g-1

Current / mA

(e) (10, 50.69)

(20, 46.11)

(50, 43.44)

(100, 36.79)

(200, 31.69)

Figure S12 (a and b) show the CV (10 mV s-1) and chronopotentiometry curves (1 A g-1) of

actived carbon and 3D-ICHA α-Ni(OH)2 at 10 mV s-1. (c-e) show the electrochemical

behavior of a high-loading full capacitor with excessive actived carbon (9.624 mg 3D-ICHA

α-Ni(OH)2 and 57.688 mg actived carbon). (c) gives the CV curves. (d) shows the

chronopotentiometry curves of the asymmetric supercapacitor.. (e) gives the specific

capacitance based on the active materials on both electrodes.

16

Table S1 Literature comparison of supercapacitor performance based on Ni(OH)2. In

particular, papers reporting powder-based α-Ni(OH)2 are exhaustively collected. The

parameters which are superior, comparable or inferior to those of 3D-ICHA α-Ni(OH)2 are

highlighted as blue, green or red, respectively.

Phase Structure Specific

surface area

/ m2 g-1

Specific charge storage

capacity / C g-1

Cycling retention Loadin

g mass

Refs.

α-Ni(OH)2 3-D inter-

connected

Hierarchical

assembly

320.2 653.1 (1 A g-1)

619.2 (2 A g-1)

554.5 (5 A g-1)

499.0 (10 A g-1)

406.0 (20 A g-1)

86.2 % （20000 cycles）

90.6 % (5000 cycles)

10 A g-1

1.5± 0.3

mg

This

work

α-Ni(OH)2 Sheet-on-sheet 115.6 289.4 (1 A g-1)

249.6 (2 A g-1)

241.5 (5 A g-1)

209.0 (10 A g-1)

166.0 (20 A g-1)

98.6 % (5 A g-1, 5000

cycles)

1.5 ±

0.3 mg

This

work

α-Ni(OH)2 Fish-scale like \ \ 95 % (10 mA, 200 cycles) \ 8

α-Ni(OH)2 Mesoporous 318 \ 85 % (0.5 A g-1, 500 cycles) \ 9

α-Ni(OH)2 Flowerlike 72.9 \ 77.9 % (50 mV s-1 2000

cycles)

\ 10

α-Ni(OH)2 Microflowers 185 \ 90 % (1000 cycles) \ 11

α-Ni(OH)2

mixed with β-

Ni(OH)2

nanosheet \ \ 91 % (10 A g-1, 500 cycles) 3-4 mg 12

Amorphous

Ni(OH)2

hollow nanobox 214.6 \ 95 % (5 A g-1 1200 cycles) 1~2 mg 13

Amorphous

Ni(OH)2

nanosphere \ \ 81 % (100 mV s-1 10000

cycles)

0.12 mg 14

NiCo2O4 array hierarchical

superstructure

36.7 348.9 (1 A g-1)

~340 (2 A g-1)

325.9 (5 A g-1)

~310 (10 A g-1)

~295 (15 A g-1)

93.6 % (10 A g-1, 3000

cycles)

\ 15

17

Table S2 Literature comparison of supercapacitor performance based on Co(OH)2. In

particular, papers reporting powder-based α-Co(OH)2 are exhaustively collected. The

parameters which are superior, comparable or inferior to those of LP α-Co(OH)2 are

highlighted as blue, green or red, respectively.

Phase Structure Specific

surface area

/ m2 g-1

Specific capacity (C

g-1)

Cycling retention Loading mass

/ mg

Refs.

α-Co(OH)2 Loosely packed 72.0 578.0 (1 A g-1)

553.8 (2 A g-1)

486.5 (5 A g-1)

432.0 (10 A g-1)

360.0 (20 A g-1)

72.4 % (10 A g-1

5000 cyckes)

1.5 ± 0.3 This

work

α-Co(OH)2 Well developed sheets 34.9 405.4 (1 A g-1)

396.0 (2 A g-1)

339.0 (5 A g-1)

305.0 (10 A g-1)

264.0 (20 A g-1)

74.5 % (10 A g-1

5000 cycles)

1.5 ± 0.3 This

work

α-Co(OH)2 Cl- intercalated,

sheet and cluster

\ \ 73 % (3 A g-1, 100

cycles)

\ 16

α-Co(OH)2 nanosheet \ \ 72.8 % (2 A g-1,

2000 cycles)

2.0 17

α-Co(OH)2 Exfoliated layers 97.2 \ no obvious decay

(0.5~2.5 A g-1, 5000

cycles)

10 18

α-Co(OH)2 nanosheets \ \ 98 % (4 A g-1 1000

cycles)

7.5 19

β-Co(OH)2 Porous 190.2 \ 93 % (1A g-1, 500

cycles)

\ 20

β-Co(OH)2 nanoplates 104 \ 92 % (2 A g-1, 1000

cycle)

25 mg 21

β-Co(OH)2 mesoporous 400.4 \ 96 % (1 A g-1, 1000

cycle)

\ 22

18

1. G. J. d. A. A. Soler-Illia, M. Jobbágy, A. E. Regazzoni and M. A. Blesa, Chem. Mater., 1999, 11, 3140-3146.

2. J. Nai, J. Wu, L. Guo and S. Yang, Crystal Growth & Design, 2012, 12, 2653-2661.

3. R. Demichelis, P. Raiteri, J. D. Gale, D. Quigley and D. Gebauer, Nat Commun, 2011, 2, 590.

4. W. J. E. M. Habraken, J. Tao, L. J. Brylka, H. Friedrich, L. Bertinetti, A. S. Schenk, A. Verch, V. Dmitrovic, P. H. H. Bomans, P. M. Frederik, J. Laven, P. van der Schoot, B. Aichmayer, G. de With, J. J. DeYoreo and N. A. J. M. Sommerdijk, Nat Commun, 2013, 4, 1507.

5. D. Gebauer, A. Völkel and H. Cölfen, Science, 2008, 322, 1819-1822.

6. H.-P. Cong, X.-C. Ren, P. Wang and S.-H. Yu, ACS Nano, 2012, 6, 2693-2703.

7. Y. Xu, K. Sheng, C. Li and G. Shi, ACS Nano, 2010, 4, 4324-4330.8. K. Wang and L. Zhang, Electrochemistry, 2013, 81, 259-261.9. H. Du, L. Jiao, K. Cao, Y. Wang and H. Yuan, ACS Appl. Mater.

Interfaces, 2013, 5, 6643-6648.10. H. Jiang, T. Zhao, C. Li and J. Ma, J. Mater. Chem., 2011, 21,

3818-3823.11. B. P. Bastakoti, H.-S. Huang, L.-C. Chen, K. C.-W. Wu and Y.

Yamauchi, Chem. Commun., 2012, 48, 9150-9152.12. P. Lu, F. Liu, D. Xue, H. Yang and Y. Liu, Electrochim. Acta,

2012, 78, 1-10.13. Y. Fu, J. Song, Y. Zhu and C. Cao, J. Power Sources, 2014, 262,

344-348.14. H. B. Li, M. H. Yu, F. X. Wang, P. Liu, Y. Liang, J. Xiao, C. X.

Wang, Y. X. Tong and G. W. Yang, Nat Commun, 2013, 4, 1894.15. Q. Zhou, X. Wang, Y. Liu, Y. He, Y. Gao and J. Liu, J.

Electrochem. Soc., 2014, 161, A1922-A1926.16. Z.-A. Hu, Y.-L. Xie, Y.-X. Wang, L.-J. Xie, G.-R. Fu, X.-Q. Jin,

Z.-Y. Zhang, Y.-Y. Yang and H.-Y. Wu, J. Phys. Chem. C, 2009, 113, 12502-12508.

17. X. Ge, C. D. Gu, X. L. Wang and J. P. Tu, J. Phys. Chem. C, 2014,

19

118, 911-923.18. Z. Gao, W. Yang, Y. Yan, J. Wang, J. Ma, X. Zhang, B. Xing and

L. Liu, Eur. J. Inorg. Chem., 2013, 2013, 4832-4838.19. T. Wu and C. Yuan, Mater. Lett., 2012, 85, 161-163.20. C. Mondal, M. Ganguly, P. K. Manna, S. Yusuf and T. Pal,

Langmuir, 2013, 29, 9179-9187.21. M. Aghazadeh, S. Dalvand and M. Hosseinifard, Ceram. Int., 2014,

40, 3485-3493.22. B. G. Choi, M. Yang, S. C. Jung, K. G. Lee, J.-G. Kim, H. Park, T.

J. Park, S. B. Lee, Y.-K. Han and Y. S. Huh, ACS Nano, 2013, 7, 2453-2460.