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).

中文翻译：

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用于稳定性高质量负载锂金属电池的多层导电梯度框架


由于亲和力和调节 Li+ 的能力不足，Li metal 倾向于在衬底材料表面积累，从而降低空间利用率并促进枝晶生长。特别是由于 Li+ 流向衬底底部的流动可能难以控制，因此高质量负载对传统框架设计来说是一个挑战。在此，受树根网络的启发，为锂金属负极设计了一种基于纤维素的梯度框架。细菌纤维素掺杂碳涂层氧化锌 （ZnO@C） 纳米颗粒用于装饰顶部，放置在铜箔上的ZnO@C纳米颗粒用于装饰底部。由于梯度导电性，Li 沉积可以从底部向上引导，以获得足够的空置空间来容纳体积变化，并充分利用整个框架以实现高质量负载。此外，LiF/Li2CO3/LiOH 富集的 SEI 层的自发形成促进了 Li+ 的运输，该层具有特殊的离子传导能力。结果，实现了 3000 小时的使用寿命和 98% 的平均库仑效率。值得注意的是，LiFePO4 全电池在实际条件下（负容量比为 1.75）表现出优异的循环稳定性和高能量密度 （102 mAh/g）。