冷进论文“Highly-Dispersed Submicron Single-Crystal Nickel-Rich Layered Cathode: Spray Synthesis and Accelerated Lithium-Ion Transport”被Small接收发表
发布时间：2021-02-19
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For conventional polycrystalline Ni-rich cathode material consisting of numerous primary particles in disordered orientation, the crystal anisotropy in charge/discharge process results in the poor rate capability and rapid capacity degradation. In this work, highly-dispersed submicron single-crystal LiNi0.8Co0.15Al0.05O2 (SC-NCA) cathode is efficiently prepared by spray pyrolysis (SP) technique followed by a simple solid-state lithiation reaction. Porous Ni0.8Co0.15Al0.05Ox precursor prepared via SP within an ultrashort residence time (< 5 s) exhibits unique properties such as moderate size distribution (D0.5=1.3 μm), uniform elemental distribution, high specific surface area and ample porous structure, which account for the high chemical activity for lithiation reaction, and are in favor of fabricating single-crystal cathode at a relatively low temperature. In this way, the contradiction between high crystallinity and cation disordering is well balanced. The resulted optimized SC-NCA shows polyhedral single-crystal morphology with moderate grain size (~1 μm), which are beneficial to shortening the Li+ diffusion path and improving the structural stability. As cathode for lithium ion batteries, SC-NCA delivers a high discharge capacity of 202 and 140 mAh g-1 at 0.1 and 10 C, respectively, and maintains superior capacity retention of 161 mAh g-1 after 200 cycles at 1C. A periodic volume change of more than 5% is evaluated by electrochemical in situ XRD while no micro-crack is observed in the cycled SC-NCA particles, indicating such submicron single-crystal Ni-rich cathode can greatly relieve the anisotropic micro-strain. This effective, continuous and adaptable strategy for preparing single-crystal Ni-rich cathode without any additive may accelerate their practical application.
