Reversible potassium-ion intercalation into graphite electrodes in glyoxal-based electrolytes

Abstract

In this work the use of the solvents 1,1,2,2-tetramethoxyethan (tetramethylglyoxal, TMG) and 1,1,2,2-tetraethoxyethan (tetraethylglyoxal, TEG) in potassium-based systems is reported for the first time. We show that utilizing electrolytes based on these solvents, potassium bis(fluorosulfonyl)imide (KFSI) and the additive vinyl ethylene carbonate (VEC), it is possible to reversibly intercalate and extract potassium-ions into and from graphite electrodes. Graphite electrodes in combination with the electrolyte 1.5 M KFSI in TEG/VEC display an intercalation capacity of 200 mAh g−1, stable for 40 cycles at C/10. This performance is comparable to that achieved with conventional organic electrolytes.

Keywords

• Potassium-ion battery
• Graphite
• Electrolyte
• Glyoxal
• Intercalation