Improved high-temperature cyclability of AlF3 modified spinel LiNi0.5Mn1.5O4 cathode for lithium-ion batteries

In this current work, high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) decorated with AlF3 thin layer was successfully synthesized and investigated for the application in Li-ion batteries (LIBs). The electrochemical properties and dissolution behavior of transition metals of the AlF3-modified LNMO electrodes were investigated, especially at elevated temperature. The well-defined and homogeneous AlF3 coating on the surface of LNMO was conducted by a facile chemical modification approach, in which the thickness of AlF3 modification layer was adjusted by adjusting the AlF3 precursor concentrations. After the optimization of the AlF3 precursor concentration, the 1 wt % AlF3-modified LNMO electrode revealed the remarkably improved cyclability especially at elevated temperature. The 1 wt% AlF3-modified LNMO electrode displayed an impressive capacity retention up to 81.7% after charged/discharged at 0.2C at elevated temperature for 100 cycles, which was superior to that of the pristine LNMO electrode (70.1%). Its improved cyclability can be ascribed to the efficient suppression of electrolyte decomposition reaction and transition metal dissolution, thus signaling promising potential in high-voltage LIBs applications.