Lithium-salt monohydrate melt As the market of an energy storage system grows, the demand for the batteries with thehigh reliability, superior safety, and high energy density has been aggrandized daily. For commercialized Li-ion batteries, thenon-aqueous electrolytes have been universally adopted owing to its wide potential window (>3 V), which is much essential for achieving high energy density. However, their high volatility, the flammability, and the toxicity pose a serious safety issue for the use in the wide fields. Indeed, several well-publicized incidents related to theLi-ion batteries have amplified the concerns about their overall safety (Schreiner et al., 2010). Aqueous electrolytes have been considered as an alternative since Dahn group suggested in 1995. Aqueous electrolytes are quite non-flammable and low-toxicity, and can also reduce facility cost for the humidity control in the manufacturing line. However, their intrinsically narrow potential windows (~1.25 V for pure water) have limited the voltage and the energy density ofthe aqueous Li-ion batteries, thus impeding their specific commercialization

1. B Y D R . S R E E R E M Y A . S
F A C U L T Y O F B I O L O G Y
Peculiar Water Environment
in a Hydrate-Melt Electrolyte

2.  Lithium-salt monohydrate melt
 As the market of an energy storage system grows, the demand for the
batteries with thehigh reliability, superior safety, and high energy density
has been aggrandized daily. For commercialized Li-ion batteries, thenon-
aqueous electrolytes have been universally adopted owing to its wide
potential window (>3 V), which is much essential for achieving high energy
density. However, their high volatility, the flammability, and the toxicity
pose a serious safety issue for the use in the wide fields. Indeed, several
well-publicized incidents related to theLi-ion batteries have amplified the
concerns about their overall safety (Schreiner et al., 2010).
 Aqueous electrolytes have been considered as an alternative since Dahn
group suggested in 1995. Aqueous electrolytes are quite non-flammable and
low-toxicity, and can also reduce facility cost for the humidity control in the
manufacturing line. However, their intrinsically narrow potential windows
(~1.25 V for pure water) have limited the voltage and the energy density
ofthe aqueous Li-ion batteries, thus impeding their specific
commercialization.

3.  the highly concentrated aqueous electrolyte of
LiN(SO2CF3)2 (LiTFSI) (22 mol kg−1), which shows
significantly widened potential window. We also reported
that the eutectic system of the LiTFSI and
LiN(SO2C2F5)2 (LiBETI) could form a room-
temperature Li-salt dihydrate melt (289mol kg−1) , in
which all water molecules were coordinated with the
cation or anion in the absence of free water molecules .
Importantly, the reduction of the water (i.e., hydrogen
evolution) at negative electrodes could be prevented by
the formation of the anion-derived SEI, which results
from the extensive coordination of imide anions to Li+ at
high level of salt concentrations.

4.  The potential window would be further extended by
availing more concentrated aqueous electrolytes with the
better SEI-forming ability. However, the Li-salt
concentration has been limited to <29 mol kg−1,
notwithstanding many efforts by several groups. This is
due to i) the limited solubility of the imide salts and ii)
the limited choice ofthe anions that can form stable SEI.
For the instance, the highest concentration of 40 mol
kg−1 was achieved by availing acetate anions, but it could
not importantly widen the potential window as compared
to imide anions, suggesting the importance of the imide
structure for the better SEI formation(Blandamer et
al.,2005).

5.  Concentrated aqueous electrolytes are promising for the high-
voltage and safe aqueous lithium-ion batteries because of their
broad potential window. For Li system, a room-temperature
dihydrate melt (27.9 mol kg−1) has been demonstrated to function
as the stable aqueous electrolyte, but the more concentrated
electrolytes have yet to be discovered due to the limited solubility of
theLi salts. Aqueous Li-ion batteries are attracting aggrandizing
attention because they are potentially low in cost, safe and the
environmentally friendly. However, their low energy density (<101
WH kg-1 based on total electrode weight), which results from the
narrow operating potential window of the water and the limited
selection of suitable negative electrodes, is problematic for their
future widespread application. Here, one explore optimized eutectic
systems of several organic Li salts and also show that a room-
temperature hydrate melt of Li salts can be availed as a stable
aqueous electrolyte in which all water molecules participate in Li+
hydration shells while retaining fluidity(De Moraes et al.,2017).

6.  MOBILITIES OF IODIDE ANIONS IN AQUEOUS
SOLUTIONS FOR APPLICATIONS IN NATURAL DYE-
SENSITIZED SOLAR CELLS Dye-sensitized solar cells
(DSSCs) composed of the aqueous electrolytes represent an
environmentally friendly, low-cost, andthe concrete
alternative to standard DSSCs and typical solar cells.
Although flammable and the toxic organic-solvent-based
electrolytes have so far been employed more than the simpler
(iodide) aqueous solutions, recently recorded efficiencies of
the water-based DSSCs suggest a trend inversion in the near
future. Here, we present a study, based on both the
experiments and ab initio molecular dynamics simulations, in
which analysis on the efficiencies of three water electrolytes
commonly employed in the DSSCs (i.e., LiI, NaI, and KI) are
reported(Han et al.,2018).

7.  GAS HYDRATE
 Gas hydrates are the unique class of chemical compounds where
moleculesof one compound (the guest material) are specifically
enclosed, without bonding chemically,within an open solid lattice
composed of another compound (a host material).These types of
configurations are known as theclathrates(Suo et al.,2016). The
guest molecules, commonlygases, are of an appropriate size such
that they fit within a cage formed bythe host material. Common
examples of gas hydrates are the carbon dioxide/water
andmethane/water clathrates. At standard pressure and
temperature,the methane hydratecontains by volume 180 times as
much methane as hydrate(Kim et al.,2014). The United
StatesGeological Survey (USGS) has specifically estimated that
there is more organic carbon containedas the methane hydrate than
all other forms of fossil fuels combined. In fact,the methane
hydrates could provide a clean source of energy for several
centuries(Pasta et al.,2012)

8. REFERNCE
 Journal of Biochemistry and Molecular Science ,
Peculiar Water Environment in a Hydrate-Melt
Electrolyte, Dr.S.Sreeremya , 2019.Vol 1(2):1-7.