UCTEA Chamber of Metallurgical & Materials Engineers
The Electrochemical Characterization of Na0.44MnO2 in
Aqueous Electrolytes
Proceedings Book
Burak Tekin, Serkan Sevinç, Rezan Demir-Çakan
Gebze Technical University - Türkiye
electrochemical
electrolytes.
Abstract
Na0.44MnO2 (NMO) was firstly synthesized by a solid state
method using Na2CO3 and MnCO3 as starting materials.
Thereafter, NMO was electrochemically characterized
through
cyclic
voltammetry
and
galvanostatic
measurements, wherein the duration of the ball milling and
the electrolyte concentration was based to evaluate the
electrochemical performance of NMO in aqueous
electrolytes. There are several parameters which effect the
electrochemical performance of a battery. From these
parameters, we examined the effect of electrolyte salt
concentration and the surface area of electrode material on
the electrochemical performance of aqueous sodium ion
batteries. Electrochemical capacity of the cathode materials
were observed to be approximately doubled when the raw
powder material was ball milled for 3 hours or the
electrolyte concentration was chosen to be 5M. Cyclic data
and galvanostatic test results show promising performance
for NMO in aqueous electrolyte media.
performance
of
NMO
in
aqueous
2. Experimental Procedure
2.1. Synthesis
Na0,44MnO2 was prepared by a solid state method[4] using
Na2CO3 and MnCO3 as starting materials. Firstly, Na2CO3
and MnCO3 were mixed in a mortar for 30 min to obtain a
homogenous mixture. This mixture was compressed for 10
min. The mixture was heated at 300 oC for 8 h to
decompose the carbonates. Obtained tablet was ground
again for 30 minutes and was compressed for 10 min. Solid
material compressed was treated at 800 oC for 12 h under
air to obtain crystalline material. Finally, synthesized
material was ground in a morter for 30 min. The raw
powders were ball milled in RETZSCH MM400
MIXER/MILL.
4Na2CO3 + 18MnCO3 + 7O2 2Na4Mn9O18 + 22CO2
(1)
1. Introduction
2.2. Materials and preparation of electrode material
The efforts on the development of energy storage and
conversion systems with high power and energy density
have been increased due to the fact that fossil fuels will be
exhausted in the near future as well as the increasing
environmental problems[1]. Rechargeable batteries are one
of the most efficient stationary or portable renewable
storage systems and are used as power supply of electronic
devices such as laptop, computer and mobile phone in the
daily life[2]. Especially, lithium ion batteries have great
commercial achievement in grid energy storage systems
because of their large power capability and energy density.
Sodium-ion batteries are currently under consideration as
an option due to the limited resource availability of lithium
and future high cost. Moreover, Sodium ion have the same
insertion chemistry with lithium as well as the abundant
availability of sodium source and its low price[3].
In this study, Na0.44MnO2 (NMO) was firstly synthesized
by a solid state method using Na2CO3 and MnCO3 as
starting materials. Thereafter, NMO was electrochemically
characterized through cyclic voltammetry and galvanostatic
measurements, wherein the duration of the ball milling and
the electrolyte concentration were used to evaluate the
796
IMMC 2016
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Polivinildiene floride (PVDF) and N-metil pirolidon
(NMP) was purchased from Sigma Aldrich and used as
received. The slurry for cathode electrode was prepared by
mixing powder NMO with Ketjen-black carbon and an
organic binder (PVDF), in a weight ratio of 80: 10: 10 in
NMP.
2.3. Electrochemical tests
Cyclic voltammetry and constant current charge/discharge
test were performed with a multi-channel potential of Bio
Logic VMP3 / Electrochemical impedance spectroscopy.
All cyclic voltammetry and galvanostatic tests were carried
out in a beaker cell, and all potential values were reported
against reference electrode (Ag/AgCl) in the range -0.1V to
0.95V.
3. Results and Discussion
CV and galvanostatic tests were performed to understand
the insertion/de-insertion mechanism of Na-ion in NMO.
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Fig. 1(a) shows cyclic voltammogram of NMO into 1M
NaNO3 at scan rate of 1 mV/s. CV graph with 3 pairs of
symmetrical redox peak means that the insertion-extraction
process of Na ion consists of multiple transportation
mechanisms. The plateaus observed in cyclic voltammetry
tests also agree with those of galvanostatic test shown in
figure 1(b).
(a)
concentrations if we focus on this charge/discharge process
for a long cycle time. The reason for the improved
performances is based on the increasing of the frictional
force among ions in electrolyte solution used.
(b)
Figure 1. (a) Cyclic voltammetry result of Na0.44MnO2 in
1M NaNO3 at scan rate 1 mV/s. (b)
Fig. 2 indicates the galvanostatic test results of NMO ball
milled for different times. The main aim of this approach is
to investigate the effect of specific surface area on the
battery performance. As it is seen in the Fig.2, the capacity
of NMO increased with increasing the ball mill
duration.due to the extended surface area of the cathode
material.
Figure 3. The discharge profile of NMO in NaNO3
electrolyte with different concentrations at 1C current
density
4. Conclusion
The effect of electrolyte salt concentration and the ball mill
duration on the electrochemical performance of NMO in
aqueous environment. These results revealed that both
types of effects could considerably influence the
electrochemical performance of NMO with aqueous
electrolyte.
Acknowledgment
Financial support from TUBITAK 1001 Project (project
no: 114Z920) was acknowledged.
References
[1] Demir-Cakan, R., et al., An aqueous electrolyte rechargeable
Figure 2. the electrochemical performance of NMO milled
for different times
As a function of cycle number, the capacity values obtained
from NMO in NaNO3 electrolyte with different
concentrations is presented in Fig. 3. As can be seen from
Fig. 3, the cell capacity values rise with increasing the
electrolyte concentration. This is because of increasing the
electrical conductivity of the electrolyte solution used. On
the other hand, the capacity fading at high electrolyte
concentrations is bigger than that of low electrolyte
Li-ion/polysulfide battery. Journal of Materials Chemistry A,
2014. 2(24): p. 9025.
[2] Demir-Cakan, R., M. Morcrette, and J.M. Tarascon, Use of
ion-selective polymer membranes for an aqueous electrolyte
rechargeable Li-ion-polysulphide battery. Journal of Materials
Chemistry A, 2015. 3(6): p. 2869-2875.
[3] Wu, W., et al., Relating Electrolyte Concentration to
Performance and Stability for NaTi2(PO4)3/Na0.44MnO2
Aqueous Sodium-Ion Batteries. Journal of the Electrochemical
Society, 2015. 162(6): p. A803-A808.
[4] Zhou, X., R.K. Guduru, and P. Mohanty, Synthesis and
characterization of Na0.44MnO2 from solution precursors.
Journal of Materials Chemistry A, 2013. 1(8): p. 2757.
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IMMC 2016
797