Enhanced Stability of LiCoO2 Cathodes in Lithium-ion Batteries Using Surface Modification by Atomic Layer Deposition |
Yoon-S. Jung, Andrew S. Cavanagh1, Anne C. Dillon2, Markus D. Groner3, Steven M. George4, Se-Hee Lee5 |
Department of Mechanical Engineering, University of Colorado at Boulder 1Department of Physics, University of Colorado at Boulder 2National Renewable Energy Laboratory 3Department of Chemistry and Biochemistry and Department of Chemical and Biological Engineering, University of Colorado at Boulder 4ALD NanoSolutions Inc. 5WCU Hybrid Materials, Seoul National University |
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ABSTRACT |
Ultrathin atomic layer deposition (ALD) coatings were found to enhance the performance of lithium-ion batteries (LIBs). Previous studies have demonstrated that $LiCoO_2$ cathode powders coated with metal oxides with thicknesses of $sim100-1000{AA}$ grown using wet chemical techniques improved LIB performance. In this study, $LiCoO_2$ powders were coated with conformal $Al_2O_3$ ALD films with thicknesses of only $sim3-4{AA}$ established using 2 ALD cycles. The coated $LiCoO_2$ powders exhibited a capacity retention of 89% after 120 charge-discharge cycles in the 3.3~4.5 V (vs. $Li/Li^+$) range. In contrast, the bare $LiCoO_2$ powders displayed only a 45% capacity retention. This dramatic improvement may result from the ultrathin $Al_2O_3$ ALD film acting to minimize Co dissolution or to reduce surface electrolyte reactions. |
Key words:
Lithium-ion batteries, Atomic layer deposition, Surface modification, Stability, Cathode |
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