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

Abstract

Cycling after storage of LiNi0.4Mn1.6O4/Li4Ti5O12 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 LiNi0.4Mn1.6O4 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 LiNi0.4Mn1.6O4 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=O functional groups. Sulfones are promising compounds to be used in high voltage Li-ion batteries thanks to their non-reactivity towards the LiNi0.4Mn1.6O4 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 LiNi0.4Mn1.6O4/Li4Ti5O12 cells as compared to EC-based electrolytes over ambient temperatures, especially at 30 °C.

Surface and Interface Issues in Spinel LiNi0.5Mn1.5O4: Insights into a Potential Cathode Material for High Energy Density Lithium Ion Batteries

“…In terms of LiNi 0.5 Mn 1.5 O 4 , changing particle sizes and shapes, ,− coating, ,− and element doping ,,− are usually adopted. In terms of electrolyte, the reported solutions include search novel high voltage electrolytes, − optimization the conventional electrolyte by other additives, − and application of ionic liquids. − …”

Recent advances in the electrolytes for interfacial stability of high-voltage cathodes in lithium-ion batteries

“…Demeaux et al reported that sulfones are promising solvents for high-voltage cathodes in LIBs, 60 although they cannot prevent the dissolution of Mn 2+ and Ni 2+ in the electrolyte due to the lack of surface films forming on the LNMO cathode. 77 Note that sulfone-based electrolytes must include an SEI former for their successful application in cells with graphite anodes. 65 The Angell group observed that the all sulfone-based electrolyte ethyl methyl sulfone (EMS)/fluoromethyl sulfone (FMS) (see the chemical structure of sulfone-based solvents in Fig.…”

“…Demeaux et al reported that sulfones are promising solvents for high-voltage cathodes in LIBs, although they cannot prevent the dissolution of Mn 2+ and Ni 2+ in the electrolyte due to the lack of surface lms forming on the LNMO cathode. 77 Note that sulfone-based electrolytes must include an SEI former for their successful application in cells with graphite anodes.…”

Chemical and Structural Stability of Lithium-Ion Battery Electrode Materials under Electron Beam

“…In order to achieve reliable battery packs for these applications, various thrusts of research and development must be conducted simultaneously, including but not limited to the design of advanced battery materials, cell configuration, circuit optimization, and diagnostics. With respect to the chemistries of electrode materials, various analytical diagnostic tools have been performed to probe chemical and structural environments from the bulk to the surface56789. In-depth diagnostic analysis can provide insights into structure-property relationships1011 as well as into failure mechanisms1213.…”