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Supporting Information
Cryptomelane K1.33Mn8O16 as a Cathode for Rechargeable Aqueous Zinc-ion Batteries
Krishnakanth Sada, Baskar Senthilkumar and Prabeer Barpanda*
Faraday Materials Laboratory, Materials Research Centre, Indian Institute of Science,
Bangalore, 560012, India
* [email protected], Phone: +91-08-2293-2783; Fax No: +91-80-2360-7316
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2019
Crystallographic information
Lattice parameters from the Rietveld refinement of the K1.33Mn8O16 (I4/m space group)
a = 9.8633(11) Å
c = 2.86514(28) Å
Volume = 278.73(8) Å3
Symmetry = Tetragonal
Symmetry space group name H-M = "I4/m"
Table S1: Atomic positions of the K1.33Mn8O16.
Atoms x y z Occ. Uiso Wykoff position
K1 0.0 0.0 0.41979 0.38431 0.06907 4e
Mn1 0.35006 0.16685 0.0 0.96531 0.00139 8h
O1 0.15444 0.20391 0.0 1.00045 0.01327 8h
O2 0.54298 0.16692 0.0 0.91304 0.03215 8h
Table S2: The area ratio of peaks Mn 2p3/2 and 2p1/2.
S.No Area Ratio2p1/2 272.41 Pristine2p3/2 535.7
1.96
2p1/2 381.72 1st discharge2p3/2 796.7
2.08
2p1/2 1068.03 1st charge2p3/2 2130.3
1.99
2p1/2 1450.04 15th discharge2p3/2 2797.0
1.92
Table S3: Comparison of the peak positions at (2θ = 12.9 and 18.2) showing shift in the ratio.
Peak-Position (2θ)
d-spacing(Å)
Counts Ratio
1st charge 12.96 6.80 363718.26 4.85 3694 0.985
1st discharge 12.76 6.93 440218.48 4.79 2026 2.172
15th charge 12.95 6.82 304518.24 4.83 3250 0.9369
15th discharge 12.52 7.06 676818.26 4.85 2809 2.409
Table S4: Comparison of prominent studies on α -MnO2 cathode still date.
Sl. No
Active Material
Discharge product
Morphology Electrolyte Capacity (mA h g-1)
Reference
1 α-MnO2 ZnSO4[Zn(OH2)3]. xH2O, MnOOH
Nanofibers ZnSO4 and MnSO4
(C/5)285
1
2 α-MnO2 ZnMn2O4 and MnOOH
MnO2 deposited on
CFP
ZnSO4 and MnSO4
(0.3C)290
2
3 α-MnO2 ZnMn2O4 Powder ZnSO4 or Zn(NO3)2
(0.5C)210
3
4 α-MnO2 Zn- birnessite Nanorods 1M ZnSO4 (C/20)205
4
5 α-MnO2 ZnMn2O4 Nanorods ZnSO4 233 5
6 KMn8O16 ZnK1-xMn8O16 Nanorods ZnSO4 and K2SO4
(1C) 77 6
7 K1.33Mn8O16 Zn- birnessite Nano particles
ZnSO4 and
MnSO4
(C/10)312
This work
Figure S1: EDS and elemental mapping of the K1.33Mn8O16 showing uniform distribution of constituent elements.
Mn
K
K
Mn
MnO
0 2 4 6 8 10 12 14 16 18 20keVFull Scale 1211 cts Cursor: 2.886 (23 cts)
Spectrum 2
6 µm
6 µm
6 µm 6 µm
K Mn O
Element Weight% Atomic%
O K 42.44 70.73K K 6.73 4.59Mn K 50.83 24.68
Figure S1: EDS and elemental mapping of the K1.33Mn8O16 showing uniform distribution of constituent elements.
Zn-Metal
K0.16MnO2
2M K2SO4
(+)
(-)
1st20th
0 2 4 6 8 10 12 14 16 18
1.0
1.2
1.4
1.6
1.8
Pote
ntia
l (V
)
Capacity (mA h g-1)
C/10
Figure S2: Galvanostatic charge/ discharge (GCD) cycles of K1.33Mn8O16 in 2M K2SO4 electrolyte. (Inset) Schematic presentation of the cell assembly.
0 2 4 6 8
1.0
1.2
1.4
1.6
1.8
Pote
ntia
l (V
vs.
Zn2+
/Zn)
Capacity (mA h g-1)
1st5th10th
Zn-Metal2M ZnSO4/
0.1M MnSO4
(+)
(-)
Carbon Paper
Figure S3: Galvanostatic charge/ discharge (GCD) cycles of carbon paper without active material in 2M ZnSO4 in 0.1M MnSO4 additive electrolyte. (Inset) Schematic presentation of the cell assembly.
1.0 1.2 1.4 1.6 1.8-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1st
2nd
3rd to 5th
Cur
rent
(mA
)
Potential (V vs. Zn2+/Zn)
Scan rate: 0.1 mV/s1.15
V
Figure S4: Cyclic voltammetry (CV) curves recorded in the potential window of 1-1.8 V at a scan rate of 0.1 mV/s.
0 20 40 60 80 100 1200
40
80
120
160
200
240
280
Cycle number
Cap
acity
(mA
h g
-1)
0
20
40
60
80
100
Cou
lom
bic
effic
ienc
y (%
)
Coulombic efficiency (%)Capacity (mA h g-1)
C/2
Figure S5: Cycling stability for 130 cycles at the current rate of C/2.
K1.33Mn8O16Coated on the Carbon paper
Separator Whatman filter paper
Zn metal
Cathode (+) Anode (-)K1.33Mn8O16
Zn-ion Battery
Figure S6: The pouch cell components and different stages of the assembly. The OCV of the two cell is 2.71 V. The assembled pouch cell was tested successfully to light a red LED.
0 50 100 150 200 250 300
1.0
1.2
1.4
1.6
1.8
Poten
tial (V
vs. Z
n2+/Z
n)
Capacity (mA h g-1)
10 15 20 25 30 35 40 45 50 55
2 (degree)
Inte
nsity
(a.u
)
Pristine
Dis 1.42 V
Dis 1.3 V
Dis 1.26 V
Discharge 1V
Char 1.51 V
Char 1.58 V
Charge 1.8 V
** *
* Zn-Birnessite
Figure S7: Ex situ XRD patterns of pristine cathode at different states of charge/discharge. During discharge and charge segments, structural transition (phase transformation) occurred after 1.26 V and 1.51 V respectively.
Figure S7: Comparative EDS spectra of pristine, 1st discharge and 1st charge electrodes.
MnK
KMn
C
MnO
0 2 4 6 8 10 12 14 16 18 20keVFull Scale 743 cts Cursor: 13.091 (0 cts)
Sum Spectrum
MnS K Mn
ZnF
K
Mn
CO
0 2 4 6 8 10 12 14 16 18 20keVFull Scale 980 cts Cursor: 13.091 (0 cts)
Sum Spectrum
MnS K MnSi
KF
Mn
Zn
C
O
0 2 4 6 8 10 12 14 16 18 20keVFull Scale 2275 cts Cursor: 12.612 (0 cts)
Sum Spectrum
1st Discharge
Pristine
1st Charge
Figure S8: Comparative EDS spectra of pristine, 1st discharge and 1st charge electrodes.
2 μm
(a)
1 μm
(b)
Figure S9: SEM images of the electrodes after (a) discharge and (b) charge showing the particles integrity. There is no significant morphological change upon battery cycling.
200 nm
200 nm 200 nm
200 nm 200 nm
Zn
KMn
O
Figure S10: TEM analysis of 15th discharged electrode. Energy-dispersive X-ray microanalysis (EDS) and elemental mapping representing the particle showing the presence of the K-ion in the structure and uniform distribution of the all elements in the particles. Further, it confirmed integrity of the particles upon the multiple (dis)charge cycles.
4 μm 4 μm
Zn
4 μm
K
4 μm
Mn
4 μm
O
4 μm
C
Figure S11: Elemental mapping of the discharged electrode.
4 μm 4 μm
Zn
4 μm
K
4 μm
Mn
4 μm
O
4 μm
C
Figure S12: Elemental mapping of the charged electrode.
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
-70
-60
-50
-40
-30
-20
-10
0
10
X in K1.33Mn8O16
Cur
rent
den
sity
(mA
g-1)
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
Pote
ntia
l (V
vs.
Zn/
Zn2+
)sada
Figure S13: Potentiostatic intermittent titration (PITT) curve during the 1st discharge revealing the phase transformation with signature bell shape curve.
References:
1. H. Pan, Y. Shao, P. Yan, Y. Cheng, K. S. Han, Z. Nie, C. Wang, J. Yang, X. Li and P.
Bhattacharya, Nat. Energy, 2016, 1, 16039.
2. W. Sun, F. Wang, S. Hou, C. Yang, X. Fan, Z. Ma, T. Gao, F. Han, R. Hu and M. Zhu, J.
Am. Chem. Soc., 2017, 139, 9775.
3. C. Xu, B. Li, H. Du and F. Kang, Angew. Chem. Int. Ed., 2012, 124, 957.
4. B. Lee, C. S. Yoon, H. R. Lee, K. Y. Chung, B. W. Cho and S. H. Oh, Sci. Rep., 2014, 4,
6066.
5. M. H. Alfaruqi, J. Gim, S. Kim, J. Song, J. Jo, S. Kim, V. Mathew and J. Kim, J. Power
Sources, 2015, 288, 320.
6. I. Cui, X. Wu, S. Yang, C. Li, F. Tang, J. Chen, Y. Chen, Y. Xiang, X. Wu and Z. He,
Front. Chem., 2018, 6, 352.