四川大学张云团队报道了获得无枝晶锂金属阳极的具有梯度分布介电性能的三维分层主体。相关研究成果发表在2024年3月14日出版的《德国应用化学》。

由于不均匀的锂离子梯度和均匀的电场引起的内部不协调，传统的导电三维（3D）主体无法有效地稳定锂金属阳极。这导致了不希望的Li“顶部生长”行为和树枝状Li生长，显著阻碍了LMA的实际应用。

该文中，研究人员构建了一个具有梯度分布介电特性的3D多级宿主（GDD-CH），该宿主有效地调节锂离子的扩散和沉积行为。它包括一种由逐层自下而上衰减Sb颗粒改性的3D碳纤维主体，通过独特的梯度介电极化，可以促进Li离子的均匀分布，降低离子浓度梯度。Sb在循环过程中转化为超离子导电Li₃Sb合金，促进了锂离子的疏浚和向底部泵送，主导了COMSOL Multiphysics模拟和物理化学表征证实的自下而上的沉积机制。

因此，在10mA/cm²的高电流密度下，实现了对称电池在2000h以上的稳定循环性能。基于GDD CH的锂金属电池在低N/P比（1.51）下，表现出显著的循环稳定性和378 Wh kg^-1的超高能量密度。

这种介电梯度设计策略拓宽了调节锂沉积机制的视角，为开发具有长耐久性的高能量密度锂金属阳极铺平了道路。

附：英文原文

Title: A 3D Hierarchical Host with Gradient-Distributed Dielectric Properties toward Dendrite-free Lithium Metal Anode

Author: Yueying Zhang, Meng Yao, Tuan Wang, Hao Wu, Yun Zhang

Issue&Volume: 2024-03-14

Abstract: The conventional conductive three-dimensional (3D) host fails to effectively stabilize lithium metal anodes (LMAs) due to the internal incongruity arising from nonuniform lithium-ion gradient and uniform electric fields. This results in undesirable Li "top-growth" behavior and dendritic Li growth, significantly impeding the practical application of LMAs. Herein, we construct a 3D hierarchical host with gradient-distributed dielectric properties (GDD-CH) that effectively regulate Li-ion diffusion and deposition behavior. It comprises a 3D carbon fiber host modified by layer-by-layer bottom-up attenuating Sb particles, which could promote Li-ion homogeneously distribution and reduce ion concentration gradient via unique gradient dielectric polarization. Sb transforms into superionic conductive Li3Sb alloy during cycling, facilitating Li-ion dredging and pumps towards the bottom, dominating a bottom-up deposition regime confirmed by COMSOL Multiphysics simulations and physicochemical characterizations. Consequently, a stable cycling performance of symmetrical cells over 2000 h under a high current density of 10 mA cm2 is achieved. The GDD-CH-based lithium metal battery shows remarkable cycling stability and ultra-high energy density of 378 Wh kg-1 with a low N/P ratio (1.51). This strategy of dielectric gradient design broadens the perspective for regulating the Li deposition mechanism and paves the way for developing high-energy-density lithium metal anodes with long durability.

DOI: 10.1002/anie.202403399

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202403399