Synthesis of heterostructure Sn|SnO2 submicron particles supported by carbon fibers as binder-free anodes for highly reversible lithium storage

Tin-based materials are considered to be next-generation anode materials for lithium-ion batteries (LIBs) due to their high theoretical capacity and safety, but their large volume expansion results in rapid capacity fading. In this work, the heterostructure of Sn|SnO2 submicron particles supported by carbon fibers and amorphous carbon layers (CF/Sn|SnO2@C) is successfully synthesized by hydrothermal and thermal treatments. Sn|SnO2 submicron particles are uniformly grown on CF and encased in the CF network. Herein, CF together with a layer of amorphous carbon not only buffers the volume change of Sn|SnO2 to prevent its pulverization and dissolution but also improves the electric and lithium ionic transportation capabilities during the lithiation/delithiation cycle. The CF/Sn|SnO2@C film can directly act as a binder-free anode for LIBs, exhibits a stable capacity of 657.6 mAh g−1 at a current density of 0.1 A g−1 after 50 cycles and presents better rate capacities than the Sn|SnO2@C comparison sample. Taking advantage of the stabilization and conductive channels of CF, this work demonstrates potential applications in the preparation of CF-based, binder-free anodes for LIBs in which metal oxide submicron particles can be effectively supported by a CF network.