LATP-coated NCM-811 for high-temperature operation of all-solid lithium battery

To achieve high-temperature operation of all-solid lithium batteries (ASLBs), LATP (Li1.3Al0.3Ti1.7(PO3)4) was coated on the surface of a high-nickel cathode material, NCM-811 powder (LiNi0.8Co0.1Mn0.1O2), by evaporation -induced self-assembly (EISA). Using EISA, the fine LATP precursor in ethanol was deposited on NCM-811 powder at loadings of 0.1-3 wt%, after which the precursor was dried and calcined at 750 degrees C. Although the X-ray diffraction (XRD) patterns of the coated samples were not significantly changed, the main peaks of NCM-811 were slightly shifted to lower angle by increasing LATP amount on NCM-811. Therefore, due to cation mixing in LATP-coated NCM-811, the lattice constant increased slightly, accompanied by a decrease in the factor c/3a. Transmission electron microscopy (TEM) showed that the thickness of the coating was 2, 5, and 8 nm for 0.5 wt %-, 1 wt%-, and 3 wt%-LATP-coated NCM-811, respectively. The LATP-coated NCM-811 samples were utilized as the active material in the composite cathode for ASLBs. The electrochemical behavior of single cells (LATP-coated NCM//composite solid electrolyte sheets//lithium metal) was evaluated at 70 degrees C. The cycle capacity retention was higher for the cell employing the cathode with 0.5 wt%-LATP-coated NCM-811 than for the other cells, with an initial discharge capacity of 138 mAh g-1 in the range of 3.0-4.1 V and capacity retention of 85% over 45 cycles. Moreover, the cycle retention of the cell was significantly improved compared with the elec-trochemical behavior of the existing ASLBs in which the cathode is prepared by simply mixing LATP powder with polyethylene oxide/salt and NCM-811 powder.

Automated summary

Coating the high-nickel cathode material surface with LATP using evaporation-induced self-assembly improves the high-temperature operation of all-solid lithium batteries. The LATP coating, which can improve lattice constant and structure through cation mixing, enhances the cycle capacity retention of the battery.