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Functional hydrogels with enhanced physiochemical properties for
highly energy dense rechargeable Zn-MnO2 batteriesAditya Upreti1, Meir Weiner1, Gautam G. Yadav1*, Jinchao Huang1, Roman Yakobov1, David J. Arnot2, Noah B. Schorr2, Nelson S.
Bell2, Timothy N. Lambert2, Sanjoy Banerjee1
*Corresponding author: [email protected]. Urban Electric Power Inc., Pearl River, NY, 2. Sandia National Laboratories, NM
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1. Develop rechargeable energy dense
Zn|MnO2 battery systems with non spill-
able characteristics using a polymer
hydrogel electrolyte.
2. Increase the energy density of Zn|MnO2
batteries by increasing utilization of the
electrodes and test in applications like
solar microgrid.
Objective
Introduction
1. Zn|MnO2 batteries are resilient to abusive
cycling conditions and safer than most
traditional batteries. But in order to
compete with the status quo of lead acid
batteries, Zn|MnO2 batteries need to have
high energy densities.
2. In order to achieve high energy densities
in Zn|MnO2 batteries, higher capacity
utilization of the electrodes is paramount.
However, accessing higher capacity
utilizations of the electrodes is challenging
because of the following reasons:
• At high utilizations, Zn mobility is high and
the probability for Zn migration to other
regions of the cell increases substantially
• MnO2 volume expansion is extensive at
high utilizations
3. These issues can be addressed by using
a hydrogel electrolyte. The hydrogel
electrolyte:
• Limits Zn mobility within the cell
• Prevents MnO2 from expanding un-
controllably
To achieve optimal battery performance the
hydrogels need to be tuned for parameters
like viscosity and free KOH concentration.
An in-situ gelation process based on the free
radical polymerization scheme of acrylic acid
has been adopted as:
i. CH2 = CHCOOH + KOH excess ⟶ CH2 =CHCOO
−K
+Potassium Acrylate + H2O
ii. CH2 = CHCOO−K
++Initiator ⟶
Potassium Polyacrylate Hydrogel
Hydrogel Preparation
Cell Preparation
1. All electrodes used in the experiments
were manufactured on the UEP electrode
line.
2. Various cell geometries were tested like
prismatic and cylindrical.
3. Control cells were cycled using liquid
electrolyte
Results & Discussion
Cell Performance:
1. 20% Utilization of Zn capacity (820mAh/g)
in a gel system
2. 20% utilization of Zn capacity (820 mAh/g)
Comparison between a hydrogel system
and a conventional electrolyte system
3. 30% utilization of Zn capacity (820mAh/g)
4. Very high utilization (>50%) of Zn capacity
(820 mAh/g)
The hydrogel electrolyte conditions were optimized
by varying the final KOH concentration in the network
and the density of crosslinking. Very low KOH
concentrations limit utilizations for both the
electrodes while high KOH concentrations decrease
sustained high energy performance.
Optimal crosslinking density was achieved using
conventional crosslinking agents and the gel point
was defined using the crossover point in the
rheological studies.
Additionally, rheological behavior was studied as a
function of KOH concentration, initiator conditions
and crosslinker content to get a hydrogel with
optimal electrochemical performance.
Conclusion
• Sustainable high energy performance for Zn-
MnO2 battery systems has been shown.
• A non spill-able hydrogel electrolyte has been
developed
Future Work
• Correlating the rheological behavior of the
hydrogel with varying preparation conditions to
electrochemical performance.
• Publishing the findings in peer reviewed articles
Acknowledgement
This work was supported by the U.S. Department
of Energy, Office of Electricity. Sandia National
Laboratories is a multi-program laboratory
managed and operated by National Technology
and Engineering Solutions of Sandia, LLC., a
wholly owned subsidiary of Honeywell
International, Inc., for the U.S. Department of
Energy's National Nuclear Security Administration
under contract DE-NA-0003525. Dr. Imre Gyuk,
Director of Energy Storage Research, Office of
Electricity is thanked for his continued support. The
views expressed herein do not necessarily
represent the views of the U.S
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Sandia National Laboratories is a multi-mission laboratory managed and
operated by National Technology & Engineering Solutions of Sandia, LLC, a
wholly owned subsidiary of Honeywell International Inc., for the U.S.
Department of Energy’s National Nuclear Security Administration under
contract DE-NA0003525.
SANDNo._