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: [email protected] (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
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