Towards room temperature operation of all-solid-state Na-ion batteries through polyester-polycarbonate-based polymer electrolytes

• In an ambition to develop solid-state Na-ion batteries functional at ambient temperature, we here explore a novel electrolyte system. Polyester-polycarbonate (PCL-PTMC) copolymers were combined with sodium bis(fluorosulfonyl) imide salt (NaFSI) to form solid polymer electrolytes for Na-ion batteries. The PCL-PTMC:NaFSI system demonstrated glass transition temperatures ranging from -64 to -11 degrees C, increasing with increasing salt content from 0 to 35 wt%, and ionic conductivities ranging from 10(-8) to 10(-5) S cm(-1) at 25 degrees C. The optimal salt concentration was clearly dependent on the level of crystallinity, which was largely determined by the CL content. At 70 and 80 mol% CL, the PCL-PTMC:NaFSI system was fully amorphous and exhibited high conductivities at lower salt concentrations. When the CL content was increased to 100 mol%, high ionic conductivities were instead observed at high salt concentrations. A decent transference number of ca. 0.5 at 80 degrees C was obtained for a polymer film containing 20 mol% CL units and 25 wt% NaFSI. Finally, a HC vertical bar 80-20(25)vertical bar Na2-xFe(Fe(CN)(6)) all-solid-state polymer electrolyte full cell was assembled to demonstrate the practical application of the material and cycled for more than 120 cycles at similar to 22 degrees C.

Subject headings

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

Keyword

All-solid-state batteries

Solid polymer electrolyte

Room temperature cycling

Sodium-ion

Publication and Content Type

ref (subject category)

art (subject category)