Facial preparation of N-doped carbon foam supporting Co3O4 nanorod arrays as free-standing lithium-ion batteries’ anode

Abstract

Here, free-standing lithium-ion batteries (LIBs) anodes were fabricated through using flexible N-doped carbon foam (NCF) derived from melamine foam as substrate and current collector based on triethylamine (TEA)-assisted burning of Co(CO3)0·5OH/NCF in air. The burning not only achieved the simple transformation from Co(CO3)0·5OH to porous Co3O4 nanorods which were arrayed on NCFs evenly, but also maintained the flexibility and integrity of NCF. The as-obtained NCF/Co3O4 composites had a robust three-dimensional framework and porous structure, which improved the electron/ion transfer, enhanced contact area with electrolyte and prevented the volume inflation in discharging/charging process. In the combusting process, TEA was transformed into N and carbon atom coating on NCF and Co3O4 nanorods, and eventually formed cross-linked NCF frame helpful to stabilize Co3O4 nanorods. When the NCF/Co3O4 composites were applied directly as free-standing LIBs’ anode, it had a higher loading mass of ∼2.5 mg cm−2 compared to traditional anode. In addition, the low charge transfer impedance and easy separation caused by the addition of traditional inactive materials were eliminated. Therefore, the flexible porous NCF/Co3O4 anode without any conductive additives and binders showed the discharge capacity of 576 mAh g−1 at 1 A g−1 after 300 cycles and excellent rate capability.