Stabilizing Sn anodes nanostructure: Structure optimization and interfacial engineering to boost lithium storage

The practical application of Sn-based material in lithium-ion batteries (LIBs) is hindered by the fast capacity fade due to the large volume expansion and the instability of solid electrolyte interface (SEI) film. Based on structural optimization and interfacial engineering theories, phosphorus-modified Sn nanoclusters encapsulated by graphene (P-Sn/NG) were designed and prepared through phosphorization process. Phosphorus modification optimize the nanostructure of the P-Sn/NG composite into nano/micro primary particles, and modify the material interface to an amorphous state. Thus, the stability of the SEI film was improved, the initial Coulombic efficiency was enhanced (82.2% on average), and the ion transmission efficiency was accelerated. As a result, the P-Sn/NG electrode showed superior cycling stability and rate capability (maintained 620.4 mA h g−1 after 3200 cycles at 5.0 A g−1) for half cells, as well as for full cells. Furthermore, the mechanism for performance improvement was revealed in detail. This work provides a new avenue for the practical application of Sn-based and other high-performance lithium-ion battery materials.