Polydopamine-induced fast lithium conductive LiAlO2 interface enables fast-charge and stable cycling of natural graphite anode
Graphite is still the dominant anode material for the state-of-the-art lithium-ion batteries. Natural graphite (NG) has the advantages of high specific capacity, abundant resources and less energy consumption. However, the high surface area, high interfacial reactivity, and the sluggish interfacial kinetics result in low initial Coulombic efficiency (ICE), poor rate performance and unsatisfactory cycle-life. Herein, we propose a uniform and fast Li + -conductive LiAlO 2 interface on NG surface with polydopamine-mediated Al 3+ anchoring route. After proper heat-treatment, the in-situ developed inorganic LiAlO 2 layer greatly reduces interfacial resistance by accelerating the interfacial Li + migration kinetics. More importantly, the inorganic LiAlO 2 layer reduces the surface reactivity of the NG anode and promotes the formation of fluorinated SEI with enhanced electron work function, high stability and fast Li + diffusion properties. As the result, the ICE of the prepared NG@PLAO anode exhibits a high ICE of 92.5 % due to the suppressed interfacial side reactions of the electrolyte components. At a high charge-discharge rate of 4C, the fabricated NCM523||NG@PLAO full cell retains 80.3 % of its nominal capacity over 800 cycles. The novel interfacial chemistry engineering well solves the uniform growth of inorganic interface on NG surface via polydopamine-mediation. It provides new thoughts to improve the fast charge and cycleability of NG anode in lithium-ion batteries.
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