All-temperature batteries enabled by fluorinated electrolytes with non-polar solvents

Fluorination generally leads to a lower melting point, higher oxidation stability, better safety characteristics, and superior SEI formation capability.

“Fluorination generally leads to a lower melting point [59], higher oxidation stability [60], better safety characteristics [61], and superior SEI formation capability [62].”

Wang's group used TTE as a cosolvent in a low-temperature electrolyte with LiFSI, FEMC, and FEC and obtained impressive low-temperature electrochemical performance.

“Recently, Wang's group used TTE as a cosolvent in an LT electrolyte (i.e., the salt is LiFSI and other cosolvents are FEMC and FEC) and obtained impressive LT electrochemical performance [62].”

Even at -85 °C, the cell can still deliver about 50% of its room-temperature capacity.

“The ionic conductivity is also superior as demonstrated by the fact that even at -85 °C, the cell can still deliver ~ 50 % of its room-temperature capacity.”

Introducing diluents such as hydrofluoroethers to form LHCE has the advantages of both good SEI formation capability and low viscosity.

“An effective measure to address this issue is to introduce diluents (i.e., hydrofluoroethers) to form the LHCE which has the advantages of both good SEI formation capability and low viscosity [62,[105][106][107].”

The Li||LiNi0.8Co0.15Al0.05O2 cell can be cycled well using a cutoff voltage of 4.3 V for charging.

“The Li||LiNi 0.8 Co 0.15 Al 0.05 O 2 cell can be cycled well using a cutoff voltage of 4.3 V for charging.”