An intermittent lithium deposition model based on bimetallic MOFs derivatives for dendrite-free lithium anode with ultrahigh areal capacity

Abstract

In the development of 3D conductive frameworks for lithium metal anode (LMA), two models have been proposed: top growth model and bottom-up growth model. However, Li tends to accumulate on the top of these 3D frameworks with homogenous lithiophilicity (top growth) and Li dendrite still forms. To address this issue, some researchers have focused on developing 3D frameworks with gradient lithiophilicity, which realized bottom-up growth of Li. Nevertheless, partial Li nucleation sites on the top of these frameworks were missed. Inspired by the two models talked above, this work firstly proposed a novel intermittent lithiophilic model for lithium deposition. To demonstrate the feasibility of this model, a bimetallic metal-organic frameworks derived ZnMn2O4-MnO nanoparticles were grown on carbon cloth for LMA. It can cycle stably under ultra-high current and areal capacity (10 mA/cm2, 10 mAh/cm2). The in-situ optical microscopy (OM) was conducted to observe the Li deposition behavior, no dendrite was found during 80 h in ester-based electrolyte while the pure Li only cycled for 2 h. What is more, it can also be well-coupled with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and solid-state electrolyte, which further prove the advantages of the intermittent model for the development of LMAs with high safety and high energy density.