Stabilizing\nLithium Metal Anodes by Fiber Clustering

Lithium metal anodes generally suffer from uncontrolled\ndendrite\ngrowth and large volume change, while traditional skeletons such as\nLi<sub>13</sub>In<sub>3</sub> and Li<sub>22</sub>Sn<sub>5</sub> are\ntoo heavy and discontinuous to offer highly efficient structural supportability\nfor composite Li anodes. In this work, lightweight and stable fiber-clustered\nskeletons, which are composed of LiB fibers and jointed Li<sub>22</sub>Si<sub>5</sub> nanoparticles, can be obtained by smelting SiB<sub>6</sub> powder and Li ingots. In addition to serving as both ionic\nand electronic conductors for composite Li anodes, the stable skeletons\nreduced volumetric fluctuation by offering uniform, heterogeneous,\nand continuous architectures while suppressing lithium dendrites with\nlow nucleation overpotential and diffusion energy barrier. As a result,\nthe Li–SiB<sub>6</sub>|Li–SiB<sub>6</sub> symmetrical\ncells achieve an ultralong lifespan over 2000 h cycling at 1 mA cm<sup>–2</sup> and 1 mA h cm<sup>–2</sup>. Eventually, the\nLi–SiB<sub>6</sub>|LiFePO<sub>4</sub> full cells exhibit a\nlong-term cyclability of 400 cycles with a high-capacity retention\nof 94.5% at 2 C, and the Li–SiB<sub>6</sub>|LiCoO<sub>2</sub> pouch cells exhibit an impressive 85% capacity retention after 350\ncycles. This work develops a new strategy to strengthen the stability\nof fibrous skeletons and minimize volume changes for dendrite-free\nLi metal anodes.