Atomic Welded Dual-Wall Hollow Nanospheres for Three-in-One Hybrid Storage Mechanism of Alkali Metal Ion Batteries

Abstract

The rational design of hierarchical hollow nanomaterials is of critical significance in energy storage materials. Herein, dual-wall hollow nanospheres (DWHNS) Sn/MoS₂@C are constructed by <i>in situ</i> confined growth and interface engineering. The inner hollow spheres of Sn/MoS₂ are formed by atomic soldering MoS₂ nanosheets with liquid Sn at high temperature. The formation mechanism of the hierarchical structure is explored by the morphology evolutions at different temperatures. The DWHNS Sn/MoS₂@C manifest abundant inner space and high specific surface area, which provides more support sites for Li⁺/Na⁺/K⁺ storage and alleviates the volume effect of tin-based electrode materials to a certain extent. The composite material manifests an outstanding specific capacity and satisfactory reversibility of lithium ion batteries (∼931 mAh g^-1 at 1 A g^-1 after 500 cycles), sodium ion batteries (∼432 mAh g^-1 at 1 A g^-1 after 400 cycles), and potassium ion batteries (∼226 mAh g^-1 at 1 A g^-1 after 300 cycles). Additionally, the morphology evolution and mechanism analysis of DWHNS Sn/MoS₂@C in alkali metal ion batteries are verified by <i>ex situ</i> measurement, which confirms the three-in-one hybrid storage mechanism, <i>i.e</i>., intercalation reaction of carbon shells, conversion reaction of MoS₂, and alloying reaction of tin.