Ultrathin surface coatings to enhance cycling stability of LiMn2O4 cathode in lithium-ion batteries

摘要: Spinel LiMn2O4 suffers from severe dissolution when used as a cathode material in rechargeable Li-ion batteries. To enhance the cycling stability of LiMn2O4, we use atomic layer deposition (ALD) method to deposit ultrathin and highly conformal Al2O3 coatings (as thin 0.6–1.2 nm) onto cathodes with precise thickness control at scale. Both bare ALD-coated are cycled specific current 300 mA g−1 (2.5 C) potential range 3.4–4.5 V (vs. Li/Li+). All exhibit significantly improved cycleability compared cathodes. Particularly, coated six ALD layers (0.9 nm thick) shows best performance, delivering an initial capacity 101.5 h final 96.5 after 100 cycles, while delivers 100.6 only 78.6 g−1. Such enhanced electrochemical performances ascribed high-quality oxide that conformal, dense, complete, thus protect active into electrolytes. Besides, can be easily optimized by accurately tuning coating via varying growth cycles.