High-capacity, low-tortuosity, and channel-guided lithium metal anode.

Zhang, Ying; Luo, Wei; Wang, Chengwei; Li, Yiju; Chen, Chaoji; Song, Jianwei; Dai, Jiaqi; Hitz, Emily M et al. · Proc Natl Acad Sci U S A · 2017

basic_science · Level V

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Abstract

Lithium metal anode with the highest capacity and lowest anode potential is extremely attractive to battery technologies, but infinite volume change during the Li stripping/plating process results in cracks and fractures of the solid electrolyte interphase, low Coulombic efficiency, and dendritic growth of Li. Here, we use a carbonized wood (C-wood) as a 3D, highly porous (73% porosity) conductive framework with well-aligned channels as Li host material. We discovered that molten Li metal can infuse into the straight channels of C-wood to form a Li/C-wood electrode after surface treatment. The C-wood channels function as excellent guides in which the Li stripping/plating process can take place and effectively confine the volume change that occurs. Moreover, the local current density can be minimized due to the 3D C-wood framework. Therefore, in symmetric cells, the as-prepared Li/C-wood electrode presents a lower overpotential (90 mV at 3 mA⋅cm<sup>-2</sup>), more-stable stripping/plating profiles, and better cycling performance (∼150 h at 3 mA⋅cm<sup>-2</sup>) compared with bare Li metal electrode. Our findings may open up a solution for fabricating stable Li metal anode, which further facilitates future application of high-energy-density Li metal batteries.