Organic ionic plastic crystal-based composite electrolyte with surface enhanced ion transport and its use in all-solid-state lithium batteries

Solid-state electrolytes have been identified as one of the most attractive
materials for the fabrication of reliable and safe lithium batteries. This work
demonstrates a facile strategy to prepare highly conductive organic ionic
plastic crystal (OIPC) composites by combination of a low weight fraction of
Li+ doped OIPC (N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)amide,
[C2mpyr][FSI]) with commercial poly(vinylidene difluoride) (PVDF) powder.
Benefiting from the enhancement of lithium ion dynamics, as evidenced by
the solid-state NMR measurements, the composite electrolyte shows an
order of magnitude higher conductivity than that of the bulk material. Lithium
metal/LiFePO4 cells incorporating the prepared composite electrolytes show
impressively high specific capacity and good cycling stability (99.8% coulombic
efficiency after 1200 cycles at 2 C, room temperature), which is the
first demonstration of long-term cycling performance at such high rate for an
OIPC-based electrolyte. The high voltage cathode, LiCo1/3Ni1/3Mn1/3O2 was
tested and good rate performance and stable capacities have been achieved.