On the limited performances of sulfone electrolytes towards the LiNi0.4Mn1.6O4 spinel

• Published in: Physical chemistry chemical physics : PCCP Vol. 15; no. 48; pp. 29 - 291
• Main Authors: Demeaux, Julien, De Vito, Eric, Lemordant, Daniel, Le Digabel, Matthieu, Galiano, Hervé, Caillon-Caravanier, Magaly, Claude-Montigny, Bénédicte
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2013
• Subjects: Chemical Sciences; Chemistry; Exact sciences and technology; General and physical chemistry; Electrolyte; Spinel; Sulfone; Spinels
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp53941e

Cycling after storage of LiNi 0.4 Mn 1.6 O 4 /Li 4 Ti 5 O 12 cells evidences lower total capacity losses for EMS-, TMS- and MIS-based electrolytes as compared to EC-based at 20 °C. The shuttle-type mechanism induced by the electrolyte oxidation is mainly present in the accumulators at this temperature, as compared to those due to the Mn 2+ and Ni 2+ dissolution. At 30 and 40 °C, EC is responsible for the polymer film formation on the LiNi 0.4 Mn 1.6 O 4 surface, which limits the transition metal ion dissolution. This results in lower reversible capacity losses compared to sulfones, but are still important: 45% at 30 °C and 70-75% at 40 °C. XPS spectra reveal that EMS does not contribute to the surface film formation on the LiNi 0.4 Mn 1.6 O 4 spinel, regardless of the cycling conditions and temperature. Only the EMC decomposition at high potential in sulfone/EMC electrolytes is responsible for an organic layer formation, which is composed of low passivating oligomers that comprise the C-O and C&z.dbd;O functional groups. Sulfones are promising compounds to be used in high voltage Li-ion batteries thanks to their non-reactivity towards the LiNi 0.4 Mn 1.6 O 4 cathode. However, this does not allow the deposition of surface films that would have enabled stopping the Mn 2+ and Ni 2+ dissolution in the electrolyte. This is responsible for degraded performances of LiNi 0.4 Mn 1.6 O 4 /Li 4 Ti 5 O 12 cells as compared to EC-based electrolytes over ambient temperatures, especially at 30 °C. Cycling after storage of LiNi 0.4 Mn 1.6 O 4 /Li 4 Ti 5 O 12 cells evidences lower total capacity losses for EMS-, TMS- and MIS-based electrolytes as compared to EC-based at 20 °C.