4-Hydroxy-2-Butanesulfonic Acid Gamma-sultone as a Bifunctional Electrolyte Additive for LiCoO₂/Graphite Batteries With Enhanced Performances

Abstract

To date, enhancing the specific energy of LiCoO 2 /graphite batteries by increasing the cut-off charging voltage through the strategy of adding multifunctional additives in the electrolyte it is still an effective method and research hotspot. In this paper, 4-hydroxy-2-butanesulfonic acid gamma-sultone (HBAG) is demonstrated as an effective bifunctional electrolyte additive to improve the electrochemical performances of 4.4 V LiCoO 2 /graphite batteries. With the addition of 1.0% HBAG in the electrolyte, a capacity retention of 94.88% after 160 cycles can be obtained when the batteries are cycled in the voltage range of 3.0−4.4 V at 25 °C, which is much higher than the batteries with the base electrolyte (54.77%). It is indicated that the HBAG additive in the electrolyte is preferentially decomposed on two electrodes, which facilitates the formation of thin and uniform films on the cathode and anode. In particular, the interface films possess excellent Li + intercalation/deintercalation properties and can prevent further decomposition of the electrolyte, resulting in battery performance improvement. These results indicate that the HBAG-containing electrolyte has promising prospects for application in high-voltage LiCoO 2 /graphite batteries with good performance.

Propanediol Cyclic Sulfate as An Electrolyte Additive to Improve the Cyclic Performance of LiNi0.6Co0.1Mn0.3O2/Graphite Pouch‐Cell at High Voltage

“…This result is comparable to the test results on the NCM613 cathode, further proving that the addition of PCS inhibited the carbonate solvent decomposition in the electrolyte. The LiF and Li x PO y F z peaks at 684.6 eV and 686.7 eV in the F 1s spectrum are derived from the LiPF 6 decomposition [26,29] . Combined with the C 1s, O 1s and F 1s spectra, a large number of electrolyte decomposition products in the baseline electrolyte are deposited on the graphite anode interface, which increases the interfacial impedance of graphite and leads to a lower discharge specific capacity of graphite/Li half‐cells.…”

“…The LiF and Li x PO y F z peaks at 684.6 eV and 686.7 eV in the F 1s spectrum are derived from the LiPF 6 decomposition. [26,29] Combined with the C 1s, O 1s and F 1s spectra, a large number of electrolyte decomposition products in the baseline electrolyte are deposited on the graphite anode interface, which increases the interfacial impedance of graphite and leads to a lower discharge specific capacity of graphite/Li half-cells. This is in accordance with the results presented in Figure 3f, after 150 cycles, the impedance is lower in the cell with the electrolyte containing PCS than that with the baseline.…”

“…Lu et al [28] demonstrated that phenyl 4fluorobenzene sulfonate (PFBS) can improve the cycling stability of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811)/graphite pouch-cell at 45 °C, because the S-containing SEI/CEI produced by PFBS improves the thermal stabilization of the electrode/electrolyte interface. Lei et al [29] proposed that 4-hydroxy-2-butanesulfonic acid gamma-sultone (HBAG) is beneficial for improving the cycle performance of LiCoO 2 /graphite cells at 4.4 V, due to the preferential decomposition of HBAG compared to the electrolyte to generate S-containing inorganic salts deposited on the electrode surface. These studies have shown that molecules containing S=O bonds in the structure can form an interface film rich in sulfur-based compounds during the electrochemical reaction and stabilize the electrode/electrolyte interface.…”