Institute of Fundamental Technological Research

In this study, spinel LiNi0.5Mn1.5O4 (LNMO) was successfully decorated with Al2O3 thin film by using atomic layer deposition (ALD) approach and evaluated as a cathode material for high-temperature applications in lithium ion batteries (LIBs). To optimize the LNMO-Al2O3 electrodes operated at elevated temperature (55 °C), the effects of Al2O3 thicknesses adjusted by controlling the ALD deposition cycle were systemically investigated. According to the series of electrochemical results, the LNMO coated with the Al2O3 thin layer in the thickness of ca. 2 nm was achieved by using one-cycle ALD and the LNMO-Al2O3 electrode exhibited superior electrochemical stability (capacity retention up to 93.7% after consecutive 150 charge/discharge cycles at 0.5 C to the pristine LNMO electrode at elevated temperature. This can be attributed to two factors: (i) the decoration of Al2O3 thin layer could not contribute remarkably to extra resistance for charge transfer; (ii) Al2O3 thin film deposition could efficiently stabilize the growth of cathode electrolyte interface (CEI) and suppress the dissolution of transition metals. Therefore, these results verify that the LNMO-Al2O3 electrode could be regarded as a promising cathode material for high-voltage LIBs, especially at elevated temperature operation.

atomic layer deposition, Al2O3 coating, lithium nickel manganese oxide, lithium-ion battery, elevated temperature