Anchoring Sn Nanoparticles in Necklace‐Like B,N,F‐Doped Carbon Fibers Enables Anode‐Less 5V‐Class Li‐Metal Batteries

Abstract Li metal batteries (LMBs), particularly with a limited Li metal anode and a 5V‐class cathode, offer significantly higher energy density compared to the state‐of‐the‐art Li‐ion batteries. However, the limited Li anode poses severe challenges to cycling stability due to low efficiency and large volume expansion issues associated with Li. Herein, we design a lightweight and functionalized host composed of Sn nanoparticles embedded into necklace‐like B,N,F‐doped carbon macroporous fibers (Sn@B/N/F‐CMFs) toward anode‐less 5V‐class LMBs. The macroporous framework can decrease the local current density to homogenize Li deposition and release structural stress to realize high areal capacity of over 40 mAh cm −2 . The lithiophilic B,N,F‐doped carbon and Sn nanoparticles can function as high‐affinity Li + binding sites to uniformize Li nucleus growth on the internal and external surface of hollow fibers. Accordingly, the Sn@B/N/F‐CMFs enable stable dendrite‐free Li plating/stripping behaviors for 1700 h even in the carbonate‐based electrolyte. When coupled with a 5V‐class LiNi 0.5 Mn 1.5 O 4 cathode, the assembled anode‐less pouch cell also displays stable cycling performance even under harsh conditions.