Designing three-dimensional lithiophilic dual-skeletons-supported lithium metal anodes for long-life lithium metal batteries

Lithium metal is one of the most promising anode materials for use in the next generation of high-energy lithium batteries. However, uneven Li deposition and large volume changes severely restrict the practical use of lithium metal anodes. Here, a dendrite-free three-dimensional (3D) composite Li anode (Li-B-Sn) with dual-skeletons was produced by a simple melting method. The unique dual-skeleton structure was composed of LiB fiber phase and Li22Sn5 phase, which enabled even Li stripping and plating processes and reduced the volume variations to improve the performance of the Li-B-Sn anode. The Li-B-Sn anode exhibited a long lifespan of 1100 h during cycling operating under a large areal capacity of 10 mA h cm−2 in a symmetrical cell. In addition, full batteries assembled with the high mass loading LiFePO4 cathode (∼11 mg cm−2) and the Li-B-Sn composite anode showed superior electrochemical performance, with a high capacity retention of 92.5% at 2 C after 430 cycles. Li-S pouch cells based on the Li-B-Sn composite anode survived over 30 cycles, which constituted better cycling stability than that of the Li-B anode. This work describes new 3D skeletons for practical use in lithium metal batteries.