A self-supported hierarchic 3D double skeleton host for highly stable lithium metal batteries

Lithium (Li) is identified as the most promising anode material for Li metal batteries but suffers from uncontrolled Li dendrites and infinite volume changes during repeated cycles. Herein, a unique self-supported hierarchic 3D Li–B–Zn composite framework with abundant lithophilic sites and outstanding structural stability is reported to address the mentioned challenges. The evenly distributed μm-sized LiZn rods act as mixed ion/electron conductors, facilitating accelerated Li+ ions transport dynamics. Additionally, these μm-sized LiZn rods are intertwined with the nm-sized LiB fibers, forming a unique hierarchic 3D framework with enhanced overall structural integrity. Moreover, this unique 3D framework also provides sufficient interior space to accommodate the volume changes during repeated Li dissolution and deposition. These synergistic features decrease the likelihood of Li dendrites growth and suppress the volume change during battery cycling, which is confirmed by various experimental characterizations. The electrochemical performance of both the Li–B–Zn symmetrical cells and the Li–B–Zn|LiFePO4 full cells exhibit long-term cyclability, superior rate performance, and high Coulomb efficiency. The reported design of a unique self-supported hierarchic 3D Li–B–Zn composite skeleton opens up new opportunities for developing next-generation Li-based anode materials.