Silicious nanowires enabled dendrites suppression and flame retardancy for advanced lithium metal anodes

Abstract The ultrahigh-energy-density lithium (Li) metal anodes have received increasing attentions for developing next-generation Li batteries, nevertheless, the safety concern and interior cycling stability originated from the intrinsically dendritic Li plating, have greatly hinder their further applications. Herein, three-dimensional networks assembled form the mineral xonotlite (Ca6Si6O17(OH)2) nanowires (XNs) with high specific surface area, strong electrolyte affinity and flame-retardant property are designed to homogenize the Li+ flux and alleviate the dendrite-caused safety hazards. Moreover, this lithiophilic scaffold promises a homogeneous Li nucleation. Particularly, a small percentage of XNs reacts into LixSiOy which accumulates in the solid electrolyte interphase (SEI) as cycling. Aided by the atomic visualization from cryo-transmission electron microscopy, the monoclinic phase of crystalline Li4SiO4 in SEI is identified, which exhibits a Li+ conduction 1000 times higher than that of Li2O according to the molecular dynamic simulation. Hence, the regulated SEI with excellent Li+ transfer capability reduces the preferential growth of high-energy Li facets, thus realizing dendrite-free Li deposition. When paired with unstable LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode, the full cells of Li-XNs-NCM811 show a capacity retention of 88% after ultralong 1600 h. This strategy would provide inspirations on rational design towards high-safety long-cycling Li metal batteries.