Effect of titanium dioxide and zinc oxide fillers on morphology, electrochemical and mechanical properties of the PEO-based nanofibers, applicable as an electrolyte for lithium-ion batteries

In this study, preparation and characterization of filler-filled nanofibrous electrolytes based on polyethylene oxide (PEO) matrix are studied. The electrospun electrolytes are fabricated by an electrospinning method, using PEO, lithium perchlorate (LiClO4) as a salt, ethylene carbonate as a plasticizer and titanium dioxide (TiO2) and zinc oxide (ZnO) as fillers. Surface morphology, fraction of free ions and crystalline phases of the electrolytes are examined. The highest ion conductivities of 0.045 mS.cm−1 and 0.035 mS.cm−1 are obtained with incorporation of 0.21 wt% of the TiO2 and ZnO fillers into the electrospun nanofibers, respectively. However, film electrolytes embedded with the TiO2 and ZnO nano particles, synthesized by a film casting method, present ion conductivities of 0.0044 mS.cm−1 and 0.0147 mS.cm−1, respectively. In addition, it is identified that ion migration follows Arrhenius behavior in the as-spun electrolytes. The filler-filled nanofibrous electrolytes loss about 40% of their capacity after 45 cycles. Moreover, mechanical strength improves in filler-filled nanofibers up to an optimum ratio. The results imply that nanofibrous structures can be a great candidate as solid-state electrolytes for lithium ion batteries.