Superlithiophilic Ag Particles Embedded in Flexible Polymer Solid Electrolyte Interface Films for Dendrite-Free Lithium Metal Anodes

A novel synergistic composite film with multifunctional merits of superlithiophilicity, high mechanical strength, fast ionic conductivity, and self-healing capability was successfully constructed by drop casting AgNO3 and PVDF-HFP mixed solution onto the metallic Li anode surfaces. After the spontaneous reaction of AgNO3 and PVDF-HFP with Li metal, the reaction produced Ag, Li3N, LiNxOy, and LiF particles together with the unreacted Ag+ ions embedded in the PVDF-HFP matrix, resulting in the formation of Ag/PH films. Benefitting from the synergistic effects, including the superlithiophilic Ag to control Li nucleation, flexible PVDF-HFP to adapt volume change, the ionic conductive Li3N/LiF to quicken the Li+ ion transfer, and the encapsulated Ag+ to self-heal cracks, the Ag/PH films could effectively induce an even nucleation/deposition of Li metal and prevent the uncontrollable growth of dendritic Li during charging/discharging cycles. Therefore, the protected Li metal anodes (Ag/PH@Li) exhibit excellent long-term cycling stability with very small overpotential in the symmetric cells. When paired with the LiNi0.8Co0.1Mn0.1O2 cathodes, the Ag/PH@Li anodes still possess improved reversible capacities of 150, 141, and 128 mAh g(-1), respectively, at the current rates of 0.5 C, 1 C, and 2 C after the 300th cycle, demonstrating their significant potential of application for the high-energy-density Li metal secondary batteries.