A novel hollow Co3O4@N-doped carbon nanobubble film composite for high-performance anode of lithium-ion batteries

Co3O4 nanomaterials and their composites are replacing carbon as anode materials of lithium-ion batteries (LIBs) because of their large theoretical capacity, low cost and high abundance. However, the volume expansion in the process of charging/discharging leads to the destruction of Co3O4 nanomaterials and thus results in poor cyclic stability, which limits their practical application seriously. Herein, a novel N-doped carbon nanobubble film (CNBF) with hollow Co3O4 nanomaterials (H-Co3O4) composites (H-Co3O4@CNBF) was prepared by proposing covalent-organic framework (COF) as template and carrier of Co2+. Using in-situ anchoring H-Co3O4 strategy, a two-step calcination method was employed to prepare H-Co3O4@CNBF. The obtained H-Co3O4@CNBF exhibited a good lithium storage ability originated from anchored H-Co3O4 nanomaterials and high cycle performance as the anode of LIBs came from the buffering of CNBF. The as-prepared H-Co3O4@CNBF showed excellent capacity of 808.0 mA h g-1 after 100 cycles at 0.2 A g-1 and outstanding cycle stability of 540.0 mA h g-1 after 200 cycles at 2 A g-1. The combination of CNBF derived from COFs with H-Co3O4 is a good strategy, which provides a new guide for the preparation of novel metal oxides and carbon composites.