Elevated temperature performance of high voltage Li1+yMn1.5Ni0.5O4−xFx spinel in window-shifted Li-ion cells.

Although the LiMn 1.5 Ni 0.5 O 4 spinel operating at 4.7 V presents some beneficial characteristics over more traditional positive electrode materials, instability issues at elevated temperature have limited its practical use so far. While we previously proposed Li 1+y Mn 1.5 Ni 0.5 O 4−x F x (LMNOF) spinel that is intrinsically stable at elevated temperatures in Li-excess half-cell configuration, we investigate herein fixed, non-excess Li-content window-shifted Li-ion systems. By utilizing Li 4 Ti 5 O 12 (LTO) or TiS 2 negative electrodes stable in broad electrolyte compositions instead of carbonaceous electrodes, we aim at limiting the Li-consuming side reactions such as the formation of solid-electrolyte interphase and enable a focus on the exploration of electrolyte compositions including additives. Utilizing such an approach, excellent fundamental stability of LMNOF in a fixed Li-content Li-ion environment is demonstrated at 55 °C with the use of relatively common electrolyte components. [ABSTRACT FROM AUTHOR]