Stable Cycling of Sodium Metal All-Solid-State Batteries with Polycarbonate-Based Polymer Electrolytes

• Solid polymer electrolytes based on high-molecular-weight poly(trimethylene carbonate) (PTMC) in combination with NaFSI salt were investigated for application in sodium batteries. The polycarbonate host material proved to be able to dissolve large amounts of salt, at least up to a carbonate:Na+ ratio of 1:1. Combined DSC, conductivity, and FTIR data indicated the formation of a percolating network of salt clusters along with the transition to a percolation-type ion transport mechanism at the highest salt concentrations. While the highest total ionic conductivities were seen at the highest salt concentrations (up to a remarkable 5 x 10(-5) S cm(-1) at 25 degrees C at a 1:1 carbonate:Na+ ratio), the most stable battery performance was seen at a more moderate salt loading of 5:1 carbonate:Na+, reaching >80 cycles at a stable capacity of similar to 90 mAh g(-1) at 60 degrees C in a sodium metal/Prussian blue cell. The results highlight the importance of the choice of salt and salt concentration on electrolyte performance as well as demonstrate the potential of utilizing polycarbonate-based electrolytes in sodium-based energy storage systems.

Ämnesord

NATURVETENSKAP  -- Kemi -- Polymerkemi (hsv//swe)

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

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

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

Nyckelord

polymer electrolytes

polycarbonates

sodium

batteries

ionic conductivity

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