Page 259 - Lindens Handbook of Batteries

MAGNeSiUM AND ALUMiNUM bATTerieS 10.11

TABLE 10.3 Cylindrical Magnesium prmary batteries
Capacity, Ah *
Diameter, Height, Weight, Conventional inside-out
battery type mm mm g structure † cell ‡
N 11.0 31.0 5 0.5
b 19.2 53.0 26.5 2.0
C 25.4 49.7 45 — 3.0
1LM 22.8 84.2 59 4.5
D 33.6 60.5 105 — 7.0
FD 41.7 49.1 125 — 8.0
No. 6 63.5 159.0 1000 — 65
* 50-h discharge rate.
† Manufacturer: rayovac Corp.
‡ Manufacturer: ACr electronics, inc., Hollywood, FL (no longer manufactured).

10.5 SIZES AND TYPES OF Mg/MnO BATTERIES
2

The cylindrical magnesium/manganese dioxide batteries were manufactured in several of the popu-
lar standard ANSi sizes, as summarized in Table 10.3. Most of the production of the conventional
battery was used for military radio transceiver applications, and mainly in the 1LM size. 12,13 The
batteries are no longer available commercially. inside-out batteries are no longer manufactured.

10.6 OTHER TYPES OF MAGNESIUM BATTERIES

Magnesium primary batteries have been developed in other structures and with other cathode materi-
als, but these designs have not achieved commercial success. Flat cells, using a plastic-film envelope,
were designed but were never produced commercially.
The use of organic depolarizers, such as meta-dinitrobenzene (m-DNb), in place of manganese
dioxide was of interest because of the high capacity that could be realized with the complete reduc-
tion of m-DNb to n-phenylenediamine (2 Ah/g). The discharge of actual batteries, while having a
flat voltage profile and a higher ampere-hour capacity than the manganese dioxide battery, had a low
operating voltage of 1.1 to 1.2 V per cell. Watthour energies were not significantly higher than for the
magnesium/manganese dioxide batteries. The m-DNb battery also was inferior at low temperatures
and high current drains. Commercial development of these batteries never materialized.
Magnesium/air batteries were studied, again because of the higher operating voltage than with
zinc (see Chap. 33). These batteries, too, were never commercialized. Magnesium, however, is
a very useful anode in reserve batteries. its application in these types of batteries is covered in
Chap. 34.
Magnesium rechargeable batteries, although not yet in commercial production, are undergoing
development and characterization. 14,15 One approach that is being evaluated uses a pure magnesium
anode, a suitable organic electrolyte such as tetrahydrofuran (THF), a suitable active salt such as
Mg(butylAlCl ) , and an intercalating cathode such as Mg Mo S (x = 0-2). This battery system has
3 2
6 8
x
a theoretical capacity of 122 mAh/g (based on cathode weight), an operating voltage of 1.1 V, and
is reported to be capable of thousands of recharges with little capacity fade. This appears to rival
the specific energy of the lead-acid and Ni-Cd systems (~60 Wh/kg). 16,17 The rate capability of the
system at present is low, but would support applications such as load leveling or solar support. 18
Another approach being evaluated utilizes a pure magnesium anode, a suitable salt/electrolyte
combination (such as 1 M C H MgF in diethyl ether), and a cathode capable of intercalating the
2
5
magnesium ion easily (such as AgO). This formulation, along with many others, provided
19