Facilitating Tetrafluoroborate Intercalation into Graphite Electrodes from Ethylmethyl Carbonate-Based Solutions

Kinetically facile intercalation of anions into graphite electrodes is essential for the good performance of dual-ion batteries. The intercalation of BF4- anions into graphite electrodes is found to be strongly impeded in the electrolyte of 1.25 m LiBF4-ethylmethyl carbonate. For this, both the strong attraction between Li+ and BF4- clusters and the special solvation state of the anion are to blame. Two strategies are employed to tailor the solvation states of ions in the solutions, which prove easy and effective in facilitating anion intercalation into graphite electrodes.