Abstract:
The R&D works on so-called ‘batteries beyond lithium-ion’ took an exponential growth in
recent days due to the overwhelming demand for secondary batteries; particularly for portable
electronic and automotive applications. Inevitably, designing a suitable electrolyte with
sufficient ambient temperature ionic conductivity is a major challenge faced by the material
research community in the field of non-lithium based secondary battery chemistries. To the
best of our knowledge, reports on solid-polymer electrolytes (SPEs) for aluminum-ion
batteries (AIBs) are lacking in the literature. In this work, an attempt has been made to
synthesize and characterize Al3+ conducting SPEs based on poly (vinyl alcohol) (PVA) host
polymer for potential applications in secondary AIBs. These SPEs were synthesized by using
standard solvent-casting technique with DI water as the solvent. Among several SPE
compositions studied in this work, the composition 𝑃𝑉𝐴20𝐴𝑙2
(𝑆𝑂4
)3
showed highest ambient
temperature ionic conductivity of 5.6 x 10-6 S cm−1
. DC polarization studies done under an
applied DC voltage of 1 V for the SS/SPE/SS configuration confirmed dominant ionic
conducting nature of these electrolytes with an ionic transference number (𝑡𝑖𝑜𝑛) of 0.99. The
conductivity vs inverse temperature variation exhibited Arrhenius behavior and the estimated
activation energies systematically decreased with ionic conductivity. The highest conducting
composition mentioned above showed lowest activation energy of 0.48 eV. The triply-charged
nature of aluminum-ions contributes for the reasonably good ambient temperature ionic
conductivity value observed in the best conducting composition.
