Improved lithium-metal/vanadium pentoxide polymer battery incorporating crosslinked ternary polymer electrolyte with N-butyl-N-methylpyrrolidinium bis(perfluoromethanesulfonyl)imide

Li metal polymer batteries incorporating crosslinked ternary PEO/PYR14TFSI/LiTFSI solid polymer electrolyte (SPE) have been prepared, using V2O5 as active cathode material. As a result of the optimization of the SPE as well as the cell assembly and cycling conditions, V2O5 lithium metal polymer batteries allow reaching 796 Wh kg−1 (of V2O5) at C/10 at 40 °C and maintaining 663 Wh kg−1 after 200 cycles at 40 °C. This is higher than the theoretical specific energy of LiCoO2 vs. Li of 609 Wh kg−1. Cycling at 80 °C allows reaching 270 mAh g−1 at C/2 and 210 mAh g−1 at 1 C, while at 20 °C it is still possible to reach a discharge capacity of almost 100 mAh g−1 at low rates. Post-cycling SEM and EDX imaging showed that, after 200 cycles at 40 °C, if the plating of Li is not fully homogeneous, no sign of dendrite growth nor obvious vanadium dissolution and redeposition on the anode side occurred.