(110c) Secondary Manganese Dioxide Electrodes for Grid-Scale Batteries

Secondary Manganese Dioxide Electrodes for Grid-Scale Batteries

Joshua W. Gallaway,
Nilesh Ingale, Michael Nyce, Yasumasa Ito, Lev Sviridov, Abhinav Gaikwad,
Steven Lever, Ali Firouzi, Sanjoy Banerjee, Daniel A. Steingart

CUNY Energy
Institute, The City College of New York

160 Convent Ave, New
York NY  10031

Manganese dioxide (MnO₂) is well-established as a
primary battery cathode, but irreversibility has generally excluded its use in
secondary batteries.  Repurposing
this chemistry as a rechargeable electrical storage medium make possible a new
era of MW-scale advanced batteries to add universal storage capability to the
electrical grid.  This would be
possible due to low cost, high availability, and safety of the materials.

There is no universal consensus on the strategy for
extending the cycle life of MnO2 electrodes, which are typically
electrolyte-filled porous electrodes also containing carbon and a binder.  Adding dopant atoms to the MnO₂
crystal structure is one.  Another
is low depth of discharge.  The
first of these renders electrochemically irreversible products (Mn₂O₃)
reversible, the second avoids their formation.  These methods are not mutually exclusive, and a combination
of them may prove successful.  In
any case, the problem is not only one of manganese electrochemistry, but also
current distribution in the electrode and interactions with the conductive
carbon matrix.

Any one of many processes may become limiting in a porous
MnO₂-carbon electrode: ionic conduction in pores, electronic conduction
in the carbon matrix, interfacial contacts, or charge transfer of the MnO₂
reaction itself.  Parallel studies
of battery cycling, half-cell cycling, ex situ material characterization, and
failure analysis must be used to identify the limiting processes in such porous
electrodes.^1,2

For this study, porous manganese dioxide cathodes were
paired with non-limiting cadmium anodes with a base cell size of ~4 Ah.  The electrolyte was quiescent 12 M KOH.
 Electrochemical impedance
spectroscopy (EIS) revealed a steady increase in cell impedance with cycle
number, although battery failure was relatively sudden, usually after 100-200
cycles.  The EIS results were
modeled to pinpoint which phenomena in the porous electrode were responsible
for increase in overall impedance.^3,4  Ex situ methods such as XRD were used to track material
changes in the electrodes.

Recent battery efforts at the CUNY Energy Institute have
incorporated parallel experimentation across many cell sizes, with the target
being large cell stacks.⁵

ACKNOWLEDGEMENTS

The authors would like to thank The Wallis Foundation and
ARPA-E under award number DE-AR0000150 for generous support.

REFERENCES

1.  J. S. Newman and C. W. Tobias, J Electrochem Soc, 109 (12), 1183-1191 (1962).

2.  J. S. Chen and H. Y. Cheh, J Electrochem Soc, 140 (5), 1213-1218 (1993).

3.  S. W. Donne and J. H. Kennedy, J Appl Electrochem, 34,
159-168 (2004).

4. S. W. Donne and J. H. Kennedy, J
Appl Electrochem, 34, 477-486 (2004).

5.  Y. Ito, M. Nyce, R. Plivelich, M. Klein, D. Steingart, S.
Banerjee, J Power Sources, 196, 2340-2345 (2011).