1,3,2-Dioxathiolane-2,2-dioxide as film-forming agent for propylene carbonate based electrolytes for lithium-ion batteries

• DTD was studied as co-solvent for pure PC based electrolytes containing LiBF4 salt.
• 10 wt% DTD is enough to build an effective and stable SEI on T44 graphite.
• Due to complete LiBF4 salt dissociation, good conductivities are enabled.
• The PC/DTD (9:1, by wt.) electrolyte achieves good D-rate test performance.
• The electrolyte is stable on NCM cathodes with good coulombic efficiencies.

1,3,2-Dioxathiolane-2,2-dioxide (DTD) was investigated as co-solvent for PC based electrolytes in combination with a graphite electrode. An amount of 10wt% of DTD in PC was used to form an effective and stable SEI on graphite during the first cycle. The decomposition of DTD takes place before PC co-intercalation may happen, thus preventing the exfoliation of graphite. Additionally, the electrolyte, 1 M LiBF4 in PC:DTD (9:1, by wt.) was proven to be compatible with NCM electrodes. Raman spectra confirmed that LiBF4 completely dissociates into ions in PC:DTD (9:1, by wt.). The electrolyte shows better conductivities in comparison to other LiBF4 based electrolytes and good rate capability up to 5 C on graphite. Therefore, LiBF4 can be used as an alternative lithium salt in lithium-ion batteries, in combination with PC based electrolytes.