科研之友
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摘要
With the rapid development in global of various applications, which including handheld electronic devices, electrical vehicles, and electric tools, cobalt-free nickel-rich layered oxide materials for application in lithium-ion batteries have received large research interest in recent years because of their high energy density and inexpensiveness. The inferior cycling stability and rate capability, however, hinder these cathode materials from commercialization. Herein, in this study, a uniform coating layer of LiF has been decorated on the surface of -LiNi0.9Mn0.1O2 cathode material via the decomposition of -LiPF6 to enhance its cyclability, rate performance, and suppress voltage decay. 0.5 wt% LiF-coated sample shows a capacity retention of 95.16% while the uncoated sample has only 79.48% after 100 cycles at 0.5 C. Meanwhile, outstanding rate performance is also displayed to be improved with 0.5 wt% coating amount. Moreover, for modification sample, the phenomenon of voltage decay during cycling is markedly alleviated (0.204 mV voltage decay per cycle). Our study suggests that the LiF coating layer effectively prevents direct contact between the electrode active materials and electrolyte, mitigates the dissolution of transition metal ions, suppresses layer-to-spinel phase transformation, and enhances structural stability. This study provides new insights in various applications for cobalt-free nickel-rich lithium-ion batteries.
