Multilayered conductive gradient framework for stability high Mass-Loading Lithium metal battery

Abstract

As a result of the affinity and inadequate ability to regulate Li⁺, Li metal tends to accumulate on the surface of substrate materials, which reduces space utilization and promotes dendrite growth. Especially since the flow of Li⁺ toward the substrate’s bottom can be tricky to control, high mass-loading is a challenge for the traditional framework design. Herein, inspired by a tree root network, a cellulose-based gradient framework was designed for the Li metal anode. Bacterial cellulose-doping carbon-coated zinc oxide (ZnO@C) nanoparticles are used for decorating the top, and ZnO@C nanoparticles placed on Cu foil decorate the bottom. Owing to the gradient conductivity, Li deposition can be directed from the bottom to up to obtain sufficient unoccupied space accommodating volume changes and fully utilize the entire frame to achieve high mass-loading. Moreover, the transportation of Li⁺ is facilitated by the spontaneous formation of the LiF/Li₂CO₃/LiOH-enriched SEI layer, which has an exceptional ability to conduct ions. As a result, a 3000 h lifespan with an average coulombic efficiency of 98 % was achieved. Notably, LiFePO₄ full cell exhibits excellent cycling stability and high energy density (102 mAh/g) under realistic conditions (negative to positive capacity ratio as 1.75).