In situ sol–gel preparation of ZrO2 in nano-composite polymer electrolyte of PVDF-HFP/MG49 for lithium-ion polymer battery

Nano-composite polymer electrolyte (NCPE), poly(vinylidenefluoride-hexafluoropropylene)-poly(methylmethacrylate) grafted natural rubber with lithium tetrafluoroborate and zirconia (PVdF-HFP/MG49-LiBF 4 -ZrO 2 ) was prepared by a facile one-pot in situ sol–gel method. The influence of zirconia nano-fillers on the electrochemical, chemical and structural properties of polymer electrolyte was investigated. The interaction of polymer electrolyte and zirconia was explored via density functional theory (DFT). Electrochemical impedance spectroscopy study showed that the optimum ionic conductivity is 2.39 × 10 −3 S cm −1 (6 wt% zirconia). X-ray diffractogram results revealed a decreasing trend of crystalline phases and no lithium salt peaks were observed upon the addition of zirconia. As a result, the LiBF 4 salt was well-solvated in the polymer matrix with a one-fold increase in lithium transference number. Remarkably, a good electrochemical stability was achieved at 6.9 V from a linear sweep voltammetry (LSV) analysis. Observations from the infrared spectra indicate that chemical interactions occurred at the carbonyl and fluoride functional groups and is further corroborated by DFT studies. Micrograph images showed that the zirconia nano-particles were successfully produced (7–15 nm). The nanocomposite polymer electrolyte possesses promising charge/discharge performance and has the potential to be applied in lithium-ion polymer battery. The high electrochemical stability and flexible nanocomposite for lithium ion polymer battery application. Highlights The sizes of ZrO 2 nano-particles are in the range of 7–15 nm. High ionic conductivity (2.39 × 10 −3 S cm −1 ) and electrochemical stability (6.9 V) was achieved for the nanocomposite polymer electrolyte sample. Nano-particle zirconia improved the lithium transference number by a fold from 0.103 to 0.216. The nanocomposite polymer electrolyte was able to maintain a good ionic conductivity (~10 −5 S cm −1 ) at a high temperature of 200 °C.