All solid lithium polymer batteries with a novel composite polymer electrolyte

Abstract

A composite polymer electrolyte based on polyethylene oxide (PEO) with a hyperbranched polymer poly[bis(triethylene glycol)benzoate] capped with an acetyl group (HBP) and a ceramic filler, BaTiO 3, was examined as the electrolyte in rechargeable lithium polymer batteries. The conductivity of the composite polymer electrolyte PEO–10 wt.% HBP with Li(CF 3SO 2) 2N–10 wt.% LiPF 6 as a lithium salt and 10 wt.% BaTiO 3 was found to be 1.6×10 −4 S/cm at 25 °C and 1.5×10 −3 S/cm at 60 °C in a O/Li ratio of 10. The lithium rechargeable batteries consisted of this highly conductive composite polymer electrolyte and the 4 V class cathode, LiNi 0.8Co 0.2O 2, showed excellent charge–discharge cycling performance. The initial cathode discharge capacity of 154 mA h/g declined only 0.1%/cycle during the first 30 cycles at 60 °C.