Study of nano-TiO2 composite polymer electrolyte incorporating ionic liquid PP12O1TFSI for lithium battery

• The ionic conductivity of the optimized nano-composite polymer electrolyte is 2 × 10− 3 S·cm− 1 at 30 °C.
• The lithium transference number of NCPE-2 is up to 0.56 at 30 °C.
• The LiFePO4/NCPE-2/Li coin-typed cell cycled at 0.5 C, shows the 1st discharge capacity up to 127.9 mAh·g− 1.

A series of novel nano-composite polymer electrolytes (NCPEs) are prepared with the ionic liquid of N-methyl-N-methoxyethylpiperidiniumbis(trifluoromethanesulfonyl)imide (PP12O1TFSI) as plasticizer and nano-sized TiO2 as additive. The effect of the ratio of TiO2 to Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) on the properties of the NCPEs are studied, such as the crystallinity and ionic conductivity. The results indicate that the nano-composite polymer electrolyte NCPE-2, that the ratio of TiO2 to PVDF-HFP is 10%, exhibits the highest ionic conductivity of 2 × 10− 3 S·cm− 1 with the lowest crystallinity. The LiFePO4/NCPE-2/Li coin-typed cell cycled at 0.5 C shows the 1st discharge capacity of 127.9 mAh g− 1 and remains 97.6% of the initial discharge capacity on the 50th cycle.