Gradient lithiation to load controllable, high utilization lithium in graphitic carbon host for high-energy batteries
Gradient lithiation to load controllable, high utilization lithium in graphitic carbon host for high-energy batteries
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DOI：
10.1016/j.nanoen.2021.106808
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发表时间：
2021-12
期刊：
影响因子：
17.6
通讯作者：
L. Tao;Bingyuan Ma;Fenqiang Luo;Zhengrui Xu;Zhifeng Zheng;Haibo Huang;P. Bai;Feng Lin
中科院分区：
文献类型：
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作者：
L. Tao;Bingyuan Ma;Fenqiang Luo;Zhengrui Xu;Zhifeng Zheng;Haibo Huang;P. Bai;Feng Lin
锂金属和碳材料之间的多相相互作用为设计用于锂金属电池的先进复合阳极提供了巨大的机会。本文报道了通过控制热浸渗时间，将单层石墨碳纸（CPs）转化为功能梯度Li/C复合阳极，并可控制LiC 6和Li金属的形成。首先形成均匀致密的亲锂LiC 6，并逐渐覆盖整个CP主体，这促进了金属Li随后均匀渗入CP。所得到的复合阳极具有独特的梯度结构，其中一个示例由5.8 mAh cm− 2的锂化LiC 6涂层和2.7 mAh cm−2的薄Li底层组成。这种梯度复合结构允许在不同的电化学条件下选择性地利用Li金属和LiC 6作为活性组分。这种复合阳极具有比许多报道的Li/C复合阳极更少的Li负载，具有稳定的多孔框架和丰富的亲锂位点，这使得在循环期间能够实现均匀的局部电场和稳定的Li金属沉积。与高容量阴极配对，与Li箔相比仅具有一小部分Li金属负载的复合阳极可以提供更好的长期循环稳定性和更高的倍率性能。
The multiphase interaction between Li metal and carbon materials provides great opportunities to design advanced composite anodes for Li metal batteries. Herein, we report the conversion of single-sheet graphitic carbon papers (CPs) to function-gradient Li/C composite anodes with controllable formations of LiC6and Li metal through controlling the thermal infiltration time. The uniform and dense lithiophilic LiC6is formed first and gradually covers the entire CP host, which promotes the subsequent homogeneous infiltration of metallic Li into the CP. The resulting composite anode has a unique gradient structure, with one example consisting of a lithiated LiC6coating of 5.8 mAh cm−2and a thin Li bottom layer of 2.7 mAh cm−2. Such a gradient composite structure allows for the selective utilization of Li metal and LiC6as the active component under different electrochemical conditions. This composite anode, with a much leaner Li loading than many reported Li/C composite anodes, has a stable porous framework and abundant lithiophilic sites, which enables uniform local electric field and stable Li metal deposition during cycling. Paired with high-capacity cathodes, the composite anode, with only a fraction of Li metal loading compared to Li foil, can provide better long-term cycling stability, and higher rate capability.