Due to the inherent advantage of Mg metal,

Due to the tremendous
progress of energy storage systems, rechargeable power sources from renewable
resources with smart energy environment having good electrochemical properties
of high safeties are highly demanded 1. Among various power sources lithium
ion batteries based on solid polymer electrolytes have many advantages which
can improve the safety and stability of batteries due to their non-leakage and
non-reactive characteristics. Eventhough it is unrivalled in its performance,
there are additional worries such as high cost, low energy and power density,
highly explosive, etc.,. The formation of dendrite during cycling in lithium
batteries causes a fatal short circuit 2. Therefore it is desired to develope
a new type of green and safer, less expensive, non dendrite rechargeable
battery system. Owing to the inherent advantage of Mg metal, magnesium (Mg) battery
has been emerged as an attractive alternate for next level batteries. Magnesium
can be electro deposited smoothly without any dendrite growth 3 and it can
also provide a higher theoretical volumetric capacity (3832 mAhcm-3)
due to the divalent nature of Mg2+ than Li (2062 mAhcm-3).
This makes the Mg battery more competitive for energy storage devices 4. In
the Earth’s crust Mg is more abundant and more widely available than Li. The
preparation of electrode with oxygen rich environment is possible with Mg
metal. These merits makes the door opened for magnesium batteries for future
generation energy storage.

In working state of a
battery the solid polymer electrolyte (SPE) serves as the separator for the
electrodes in open state as well as the ion conductor medium between the
electrodes. Due to their potential applications such as suitable for flexible
type, leak proof and light weight, novel materials for the fabrication of ion
conducting devices SPE have been widely studied for the past two decades 5.For the preparation
of SPE’s the synthetic polar polymers namely; poly(ethylene oxide) (PEO),
poly(methylmethacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(acrylonitrile)
(PAN), poly(vinyl pyrrolidone) (PVP) etc. are frequently used as host matrix
for the preparation of SPE’s. Traditionally, the conduction mechanism of polymer
electrolytes is based on the transport of the metal ion which is closely
coupled to the polymer chains. The ionic transport of SPE occurs only in the
amorphous polymer regions than in crystalline region and is often governed by
the segmental motion of the polymer chain6. The SPE forms the complexes of
polymer with the ions of the added salt which have high amorphicity. The low
ionic conductivity at ambient temperature limits the SPE’s for several
technological applications in which the dynamics of polymer chains is critical
for the ions transportation. The ionic conductivity of the SPE can be increased
by number of approaches such as (i) use of conventional plasticizers like EC,
PC, DEC etc. (ii) dispersion of inorganic filler like SiO2,Al2O3,
CNT, TiO2 etc. (iii) copolymerization (iv) blending etc. Among
various approaches, concerning with the wide variety of application prospects,
polymer blending technique has been used for developing and designing new
polymeric materials7. The two main advantages of polymer blending are (i)
suitable control of physical properties by compositional changes and (ii)
simplification of synthesis conditions. Recently Hema et.al synthesized a
single Li-ion polymer for polyvinyl alcohol (PVA) which was blended with PVdF
and LiCF3SO3& TiO2 as nano filler to form
Li-ion electrolyte with conductivity as high as 3.7 x 10-3 Scm-1
at room temperature 8. When compared to pure PVA (2 x 10-10 Scm-1)
the PVA/PAN blend polymer electrolyte (BPE) with 3M LiClO4 was
reported to have an improved conductivity of 3.76 x 10-3 Scm-19.
Anji etal., has reported that the polymer electrolyte having 30 wt.% of Mg(NO3)2
with PVA–PVP polymer blend has high ionic conductivity of 3.44×10?5 S/cm
10. Further to accomplish better conductivity many blend electrolytes have
been reported based on PVC/PEO 11, PVA/PMMA 12 , PVdFHFP/PAN
13 and so on. Among various polymers Poly vinyl alcohol (PVA) is a
biodegradable, biocompatible, and non-toxic inexpensive synthetic polymer with
excellent film forming properties. In aqueous blending PVA with long range
hydrogen bond forming ability results into better complex formation with
enhanced physical and chemical properties. The preparation and characterization
of PVA based BPE membranes were assessed for the battery applications 14,15.
By changing various crystallization conditions and the blend component ratios
composed by PVA and other crystalline polymers can modulate the crystalline
structure of the blend. In this order PAN is a suitable candidate to create a
blend with PVA. PAN is a semicrystalline, synthetic resin prepared by the
polymerization of acrylonitrile. PAN is a special conjugate polymer which can
permit faster ionic mobility and it is easily soluble in DMF. Hai-Kuan Yuan et
al., studied about the dehydration of ethyl acetate solution by pervaporation
using PVA/PAN hollow fiber composite membrane 16, The effect of the reaction
of epichlorohydrin with hydrolyzed starch-g-PAN (HSPAN)/PVA blend films has
been reported by Dae Hyun Kim et al.17, Xiao-Hua Maa et al. 18 studied the
preparation and characterization of PFSA–PVA–SiO2/PVA/PAN difunctional hollow fiber
composite membranes. When PVA and PAN are mixed the interactions between them
were expected to occur through interchain hydrogen bonding. PVA-PAN having good
charge storage capacity and their electrical and optical properties makes it to
be a good potential material when added with salt19. It has been optimized
that the system comprising 
92.5PVA:7.5PAN has the highest conductivity 1.2×10-7 S cm-1
20. Based on ammonium and lithium salts there have been some studies on this
optimized blend composition 19,21-23. Literature survey reveals that only
very little attention has been given to the polymer electrolytes based on
PVA–PAN blend in which multivalent cations are the mobile species. Girish Kumar
and Munichandraiah 24,25 have successfully constructed working magnesium
cells for the gel polymer electrolytes and manganese oxide (MnO2) as
cathode by using poly(vinylidenefluoride) (PVDF) and poly(methylmethacrylate)
(PMMA) as polymer hosts. Osman et al. 
has reported that 15 % Mg(ClO4)2 and 20 % Mg (CF3SO3)2  could coordinate with PMMA gel polymer
electrolyte system to give the maximum ionic conductivity of 3.31 x 10-3
Scm-1 and 1.27 x 10-3 Scm-1 respectively26.

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