Despite the lithium metal has been considered as an ideal anode for boosting the energy density of Li-ion batteries, thermodynamic dendritic lithium growth and aggressive degradation of Ni-rich cathode during charge process hinder the practical application of Li metal/Ni-rich Li[Ni_xCo_yMn_1-x-y]O₂ battery. Herein, we propose an effective multifunctional nitrile type additive. This additive-induced lithium metal anode SEI layer is robust and compact, and thus beneficial to obtain mound-like Li platting morphologies during charge. This uniform and dendrite-free morphology significantly enhanced the safety issues and improved the coulombic efficiency. At the same time, this additive also enhanced the stability of electrolyte/cathode interface by strong coordination between nitrile group (additive) and transition metal (cathode active material) during charge. This coordination effectively hinders decomposition of carbonate solvent on the cathode/electrolyte interface. As a result, Li metal/Ni-rich Li[Ni_0.73Co_0.10Al_0.02Mn_0.15]O₂ battery is able to achieve an excellent cycle retention even when applying the high current density (1.8 mA cm^-2).

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