(402d) Understanding the Effect of ZINC and Achieving LONG CYCLE Life in Cu-Intercalated Bi-Birnessite/ZINC Batteries

UNDERSTANDING
THE EFFECT OF ZINC AND ACHIEVING LONG CYCLE LIFE IN Cu-INTERCALATED
Bi-BIRNESSITE/ZINC BATTERIES

Manganese dioxide (MnO₂)/Zinc
(Zn) batteries have high volumetric energy densities > 400Wh/L (1), which
make them ideal for use in grid applications as safe, low cost and
non-flammable energy storage devices. However, their use has been curtailed to
primary applications because of the irreversible nature of MnO₂
beyond 5-10% of its 2^nd electron capacity of 617mAh/g (2). Recently,
we solved the issue of MnO₂ rechargeability by using a layered
polymorph called birnessite mixed with bismuth oxide intercalated with Cu ions
(Cu intercalated Bi-birnessite) (3). The Cu-intercalated Bi-birnessite was
shown to cycle near the 2^nd electron capacity for thousands of
cycles. For energy dense batteries where areal and volumetric capacities are
important parameters, it was also shown to cycle at very high areal capacities
of 10-29mAh/cm² against a sintered NiOOH counter-electrode for
thousands of cycles. However, for true applicability in practical energy dense
batteries its pairing with a Zn anode is essential. The use of Zn anodes has
also presented problems as it is the source of zincate ions in electrolyte that
react with the cathode, MnO₂, to form electro-inactive phase called haeterolite
(ZnMn₂O₄) (4,5). The best reported cycle life data for
high depth-of-discharge (DOD) birnessite cathodes with Zn anodes had been 50
cycles (4) till our recent publication, which showed over 90 cycles (3).

In this presentation, we
report the effect of zincate ions on the Cu-intercalated Bi-birnessite cathodes
beyond 100 cycles (6). The Cu-intercalated Bi-birnessite cathodes when paired
with Zn anodes are shown to deliver 160Wh/L and cycle reversibly for over 100
cycles. The Cu ions play an important role in mitigating the detrimental effect
of zincate ions in the 100 cycles; however, the zincate ions eventually poison
the cathode to form ZnMn₂O₄. The mechanism through which
ZnMn₂O₄ is formed is presented in detail with the aid of
electroanalytical and spectroscopic methods.  A solution of trapping the
zincate ions is also presented, where the membrane that is used successfully
traps the zincate ions from interacting with the cathode and thus, extend cycle
life to over 900 cycles as shown in Figure 1. This is the best reported cycle
life data with a manganese dioxide cathode accessing the near 2^nd
electron capacity paired with Zn anodes.

Figure 1. A
Cu-intercalated Bi-birnessite cathode paired with Zn anode achieving cycle life
greater than 900 cycles with specialized membrane.

Reference:

1] Gallaway, J. W.;
Hertzberg, B. J.; Zhong, Z.; Croft, M.; Turney, D. E.; Yadav, G. G.; Steingart,
D. A; Erdonmez; C. K.; Banerjee, S. “Operando identification of the point of
[Mn₂]O₄ spinel formation during γ-MnO2 discharge
within batteries” Journal of Power Sources 321, 135-142 (2016).

2] Ingale,
N. D.; Gallaway, J. W.; Nyce, M.; Couzis, A.; Banerjee, S., “Rechargeability
and economic aspects of alkaline zinc­manganese dioxide cells for electrical
storage and load leveling,” Journal of Power Sources 276, 7­18
(2015)

3] Yadav, G. G.; Gallaway, J. W.;
Turney, D. E.; Nyce, M.; Huang, J.; Wei, X.; Banerjee, S. “Regenerable
Cu-intercalated MnO₂ layered cathode for highly cyclable energy
dense batteries” Nat. Commun. 8, 14424 (2017).

4] Bai, L.; Qu, D. Y.; Conway, B. E.; Zhou, Y. H.;
Chowdhury, G.; Adams, W. A. “Rechargeability of a Chemically Modified
MnO2/Zn Battery System at Practically Favorable Power Levels” J. Electrochem.
Soc. 140, 884-889 (1993).

5] Huang, J.; Yadav, G. G.; Gallaway, J. W.; Nyce, M.;
Banerjee, S. “Calcium Hydroxide Membrane As a Separator to Immobilize
Zincate Ions in Secondary Alkaline Batteries” ECS Meeting, Abstract
MA2016-01 490 (2016).

6] Yadav, G. G.; Wei, X; Huang, J.; Gallaway, J. W.;
Turney, D. E.; Nyce, M.; Secor, J.; Banerjee, S., paper submitted (2017).