The graphite-based hybrid Li-ion/metal anode holds great promise to be one of the ultimate anode choices, owing to its high specific capacity (often up to 500 mAh/g), obviously superior to 372 mAh/g of the commercial graphite anode. Unfortunately, Li deposition on the top surface of the conductive graphite host can easily drive Li dendrite growth, dead Li accumulation, and the blockage of Li⁺ transport pathways, leading to low host space utilization and cycling stability deterioration. Herein, a graphite host with lithiophilicity and reactive activity dual-gradient is constructed by integrating a surface insulation passivation and a bottom lithiophilicity modification to realize the “bottom-up” deposition behavior for hybrid Li-ion/metal anode. The conformal coating layer of electrical insulating and lithiophobic polymer can efficiently retard Li⁺ reduction and deposition on the top surface of the conductive host, while the decorated Ag nanoparticles with high lithiophilicity on the host bottom enable much lower Li nucleation barrier, thereby guiding the preferential bottom-up Li deposition. Li dendrite growth is effectively inhibited and the synergistic effects realize high space utilization of the host. Consequently, the hybrid graphite-Li anodes with 600 mAh/g of lithiation capacity (∼3.0 mAh cm⁻²) deliver significantly improved cycling stability over 500 cycles with a negligible capacity fading rate of 0.05 % per cycle at 1 C in LiFePO₄-based full-cells (N/P ratio = 1.9).

中文翻译：

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双梯度主机可实现自下而上的锂沉积到锂离子/金属混合阳极，使用寿命长


石墨基混合锂离子/金属负极有望成为最终的阳极选择之一，因为它具有高比容量（通常高达 500 mAh/g），明显优于商用石墨负极的 372 mAh/g。不幸的是，导电石墨主体顶面的 Li 沉积很容易驱动 Li 枝晶生长、死 Li 积累和 Li⁺ 运输途径的阻塞，导致宿主空间利用率低和循环稳定性恶化。本文通过集成表面绝缘钝化和底部亲锂改性构建了具有亲锂性和反应活性双梯度的石墨主体，以实现混合锂离子/金属负极的“自下而上”沉积行为。电绝缘和疏锂聚合物的保形涂层可以有效地延缓导电主体顶面的 Li⁺ 还原和沉积，而主体底部具有高亲石性的装饰 Ag 纳米颗粒使 Li 成核势垒大大降低，从而引导优先自下而上的锂沉积。锂枝晶生长得到有效抑制，协同效应实现宿主空间利用率高。因此，具有 600 mAh/g 锂化容量 （∼3.0 mAh ^cm-2） 的杂化石墨-锂负极在 500 次循环中提供了显着提高的循环稳定性，在 1 C 下每个循环的容量衰减率为 0.05% 可以忽略不计在基于 LiFePO₄ 的全电池中（N/P 比 = 1.9）。