Compatibility of polymer electrolyte based on N-methyl-N-propylpiperidinium bis(trifluoromethanesulphonyl)imide ionic liquid with LiMn2O4 cathode in Li-ion batteries

• Presented work concerns a LiMn2O4 as a cathode in lithium-ion battery.
• Non-flammable polymer electrolyte with ionic liquid was synthesized by the casting technique.
• Satisfactory capacity of the LMO working with polymer electrolyte based on IL was obtained.

LiMn2O4 (LMO) was examined as a cathode material for the lithium-ion battery, working together with a polymer electrolyte (PE) based on the PVdF polymer network, MePrPipNTf2 + LiNTf2 ionic liquid (MePrPip: N-methyl-N-propylpiperidinium cation, NTf2 is bis(trifluoromethanesulphonyl)imide anion) and vinylene carbonate (VC) as the SEI forming additive. The polymer electrolyte was prepared by the casting technique. The LiMn2O4 cathode in LMO/PE/Li and LMO/PE/Li4Ti5O12 (LTO) cells was characterized by scanning electron microscopy (SEM), cyclic sweep voltammetry (CV), electrochemical impedance spectroscopy (EIS), cyclic sweep voltammetry (CV) and galvanostatic charging/discharging. Room temperature ionic conductivity of the LiNTf2 + MePrPipNTf2 + PVdF and LiNTf2 + MePrPipNTf2 + PVdF + VC polymer electrolytes was 0.46 mS cm− 1 and 4.4 mS m− 1, respectively. The LiMn2O4 cathode with quaternary PE exhibited a good specific capacity of 117 mAh g− 1 and 105 mAh g− 1 at low and medium rates. The full LMO/LTO cell using PE as a separator displayed good cycling performances (ca. 103 mAh g− 1 after 160 cycles). This result indicates that the non-flammable, quaternary LiNTf2 + MePrPipNTf2 + PVdF + VC polymer electrolyte can be safely used in combination with a manganese cathode in Li-ion batteries.