<s>
Both	O
non-rechargeable	O
primary	B-Algorithm
cell	I-Algorithm
and	O
rechargeable	B-Architecture
secondary	B-Architecture
cell	I-Architecture
chemistries	O
have	O
been	O
investigated	O
.	O
</s>
<s>
Magnesium	O
primary	B-Algorithm
cell	I-Algorithm
batteries	I-Algorithm
have	O
been	O
commercialised	O
and	O
have	O
found	O
use	O
as	O
reserve	O
and	O
general	O
use	O
batteries	O
.	O
</s>
<s>
Magnesium	O
secondary	B-Architecture
cell	I-Architecture
batteries	O
are	O
an	O
active	O
topic	O
of	O
research	O
,	O
specifically	O
as	O
a	O
possible	O
replacement	O
or	O
improvement	O
over	O
lithium-ion	O
–	O
based	O
battery	O
chemistries	O
in	O
certain	O
applications	O
.	O
</s>
<s>
A	O
significant	O
advantage	O
of	O
magnesium	O
cells	O
is	O
their	O
use	O
of	O
a	O
solid	O
magnesium	O
anode	O
,	O
allowing	O
a	O
higher	O
energy	O
density	O
cell	O
design	O
than	O
that	O
made	O
with	O
lithium	B-Language
,	O
which	O
in	O
many	O
instances	O
requires	O
an	O
intercalated	O
lithium	B-Language
anode	O
.	O
</s>
<s>
A	O
number	O
of	O
chemistries	O
for	O
reserve	B-Algorithm
battery	I-Algorithm
types	O
have	O
been	O
researched	O
,	O
with	O
cathode	O
materials	O
including	O
silver	O
chloride	O
,	O
copper(I )	O
chloride	O
,	O
palladium(II )	O
chloride	O
,	O
copper(I )	O
iodide	O
,	O
copper(I )	O
thiocyanate	O
,	O
manganese	O
dioxide	O
and	O
air	O
(	O
oxygen	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
water-activated	O
silver	O
chloride/magnesium	O
reserve	B-Algorithm
battery	I-Algorithm
became	O
commercially	O
available	O
by	O
1943	O
.	O
</s>
<s>
The	O
magnesium	O
dry	O
battery	O
type	O
BA-4386	B-Algorithm
was	O
fully	O
commercialised	O
,	O
with	O
costs	O
per	O
unit	O
approaching	O
that	O
of	O
zinc	O
batteries	O
–	O
in	O
comparison	O
to	O
equivalent	O
zinc-carbon	O
cells	O
the	O
batteries	O
had	O
greater	O
capacity	O
by	O
volume	O
,	O
and	O
longer	O
shelf	O
life	O
.	O
</s>
<s>
The	O
BA-4386	B-Algorithm
was	O
widely	O
used	O
by	O
the	O
US	O
military	O
from	O
1968	O
until	O
ca.1984	O
when	O
it	O
was	O
replaced	O
by	O
a	O
lithium	B-Language
thionyl	O
chloride	O
battery	O
.	O
</s>
<s>
General	O
Electric	O
produced	O
a	O
magnesium	O
–	O
air	O
battery	O
operating	O
in	O
neutral	O
NaCl	B-Application
solution	O
as	O
early	O
as	O
the	O
1960s	O
.	O
</s>
<s>
The	O
magnesium	O
–	O
air	O
battery	O
is	O
a	O
primary	B-Algorithm
cell	I-Algorithm
,	O
but	O
has	O
the	O
potential	O
to	O
be	O
'	O
refuelable	O
 '	O
by	O
replacement	O
of	O
the	O
anode	O
and	O
electrolyte	O
.	O
</s>
<s>
Secondary	O
magnesium	O
ion	O
batteries	O
,	O
involving	O
the	O
reversible	O
insertion	O
and	O
removal	O
of	O
Mg2+	O
ions	O
in	O
anodes	O
and	O
cathodes	O
during	O
charging	O
and	O
discharging	O
,	O
have	O
been	O
the	O
subject	O
of	O
intensive	O
research	O
as	O
a	O
possible	O
replacement	O
or	O
improvement	O
on	O
lithium-ion	O
battery	O
technologies	O
in	O
certain	O
applications	O
:	O
In	O
comparison	O
to	O
metallic	O
lithium	B-Language
as	O
an	O
anode	O
material	O
,	O
magnesium	O
has	O
a	O
(	O
theoretical	O
)	O
energy	O
density	O
per	O
unit	O
mass	O
under	O
half	O
that	O
of	O
lithium	B-Language
(	O
18.8	O
MJ/kg	O
(	O
~	O
2205	O
mAh/g	O
)	O
vs.	O
42.3	O
MJ/kg	O
)	O
,	O
but	O
a	O
volumetric	O
energy	O
density	O
around	O
50%	O
higher	O
(	O
32.731	O
GJ/m3	O
(	O
3833	O
mAh/mL	O
)	O
vs.	O
22.569	O
GJ/m3	O
(	O
2046	O
mAh/mL	O
)	O
.	O
</s>
<s>
In	O
comparison	O
to	O
metallic	O
lithium	B-Language
anodes	O
,	O
magnesium	O
anodes	O
do	O
not	O
exhibit	O
dendrite	O
formation	O
,	O
albeit	O
only	O
in	O
certain	O
nonaqueous	O
solvents	O
and	O
at	O
current	O
densities	O
below	O
ca	O
.	O
</s>
<s>
Such	O
dendrite-free	O
Mg	O
deposition	O
allows	O
for	O
magnesium	O
metal	O
to	O
be	O
used	O
without	O
an	O
intercalation	O
compound	O
at	O
the	O
anode	O
,	O
thus	O
raising	O
the	O
theoretical	O
maximum	O
relative	O
volumetric	O
energy	O
density	O
to	O
around	O
5	O
times	O
that	O
of	O
a	O
lithium	B-Language
graphite	O
electrode	O
.	O
</s>
<s>
Additionally	O
,	O
modeling	O
and	O
cell	O
analysis	O
have	O
indicated	O
that	O
magnesium-based	O
batteries	O
may	O
have	O
a	O
cost	O
advantage	O
over	O
lithium	B-Language
due	O
to	O
the	O
abundance	O
of	O
magnesium	O
on	O
earth	O
and	O
the	O
relative	O
scarcity	O
of	O
lithium	B-Language
deposits	O
.	O
</s>
<s>
In	O
2000	O
,	O
Israeli	O
researchers	O
reported	O
dendrite-free	O
Mg	O
plating	O
in	O
AlCl3-ether	O
electrolytes	O
that	O
show	O
a	O
fairy	O
high	O
(	O
>2	O
V	O
vs.	O
Mg/Mg2	O
+	O
)	O
anodic	O
voltage	O
stability	O
limit	O
.	O
</s>
<s>
A	O
key	O
drawback	O
to	O
using	O
a	O
metallic	O
magnesium	O
anode	O
is	O
the	O
tendency	O
to	O
form	O
a	O
passivating	O
(	O
non-conducting	O
)	O
surface	O
layer	O
when	O
recharging	O
,	O
blocking	O
further	O
charging	O
(	O
in	O
contrast	O
to	O
lithium	B-Language
's	O
behaviour	O
)	O
.	O
</s>
<s>
In	O
addition	O
to	O
bismuth	O
,	O
tin	B-Protocol
and	O
antimony	O
have	O
also	O
been	O
used	O
in	O
compound	O
insertion	O
electrodes	O
for	O
magnesium	O
ion	O
batteries	O
.	O
</s>
<s>
The	O
compound	O
Mg(BPh2Bu2 )	O
2	O
was	O
used	O
in	O
the	O
first	O
demonstrated	O
rechargeable	B-Architecture
magnesium	O
battery	O
,	O
but	O
its	O
usefulness	O
was	O
limited	O
by	O
electrochemical	O
oxidation	O
(	O
i.e.	O
</s>
<s>
The	O
current	O
wave	O
of	O
interest	O
in	O
magnesium-metal	O
batteries	O
started	O
in	O
2000	O
,	O
when	O
an	O
Israeli	O
group	O
reported	O
reversible	O
magnesium	O
plating	O
from	O
mixed	O
solutions	O
of	O
magnesium	O
chloride	O
and	O
aluminium	O
chloride	O
in	O
ethers	B-Application
,	O
such	O
as	O
THF	O
.	O
</s>
<s>
One	O
drawback	O
compared	O
to	O
lithium	B-Language
is	O
magnesium	O
's	O
higher	O
charge	O
( +2	O
)	O
in	O
solution	O
,	O
which	O
tends	O
to	O
result	O
in	O
increased	O
viscosity	O
and	O
reduced	O
mobility	O
in	O
the	O
electrolyte	O
.	O
</s>
<s>
For	O
cathode	O
materials	O
a	O
number	O
of	O
different	O
compounds	O
have	O
been	O
researched	O
for	O
suitability	O
,	O
including	O
those	O
used	O
in	O
magnesium	O
primary	B-Algorithm
batteries	I-Algorithm
.	O
</s>
<s>
Cobalt	O
based	O
spinels	O
showed	O
inferior	O
kinetics	O
to	O
magnesium	O
insertion	O
compared	O
to	O
their	O
behaviour	O
with	O
lithium	B-Language
.	O
</s>
<s>
In	O
2014	O
a	O
rechargeable	B-Architecture
magnesium	O
battery	O
(	O
conversion-type	O
)	O
was	O
reported	O
utilizing	O
an	O
ion	O
exchanged	O
,	O
olivine	O
type	O
MgFeSiO4	O
cathode	O
with	O
a	O
bis(trifluoromethylsulfonyl )	O
imide/triglyme	O
electrolyte	O
–	O
the	O
cell	O
showed	O
a	O
capacity	O
of	O
300	O
mAh/g	O
with	O
a	O
voltage	O
of	O
2.4	O
V	O
.	O
MgMnSiO4	O
has	O
also	O
been	O
investigated	O
as	O
a	O
potential	O
Mg2+	O
insertion	O
cathode	O
.	O
</s>
<s>
In	O
2016	O
a	O
porous	O
carbon/iodine	O
combination	O
cathode	O
was	O
reported	O
as	O
a	O
potential	O
alternative	O
to	O
Mg2+	O
insertion	O
cathodes	O
-	O
the	O
chemistry	O
was	O
reported	O
as	O
being	O
potentially	O
suitable	O
for	O
a	O
rechargeable	B-Architecture
flow	B-Algorithm
battery	I-Algorithm
.	O
</s>
