Extending the low-temperature operation of sodium metal batteries combining linear and cyclic ether-based electrolyte solutions

Screening of single-solvent electrolytes at low temperaturesWe screened different electrolyte solutions at −35 °C using a variety of salt-solvent combinations. Ethers with low melting points, including diethylene glycol dimethyl ether (DEGDME), 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL), were chosen as candidate solvents (Supplementary Table 2). A variety of conducting salts, including sodium hexafluorophosphate (NaPF6), sodium trifluoromethanesulfonate (NaOTf), sodium perchlorate (NaClO4), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and sodium bis(fluorosulfonyl)imide (NaFSI), were investigated as candidate salts. The salt concentration in the solvent was kept at 1 M for the solubility screening of these single-solvent electrolytes at low temperatures. The results (Supplementary Table 3) suggest that the solubility of NaPF6 cannot reach a 1 M concentration…

Read more…