In situ encapsulation of Co/Co3O4 nanoparticles in nitrogen-doped hierarchically ordered porous carbon as high performance anode for lithium-ion batteries

This work explores the fabrication of Co/Co 3 O 4 nanoparticles encapsulated in nitrogen-doped hierarchically ordered porous carbon (Co/Co 3 O 4 /NHPC) and investigates their electrochemical performance for lithium-ion batteries (LIBs). Co/Co 3 O 4 /NHPC is obtained from a typical dual-template (silica opal is employed as a hard template and F127 (EO 106 PO 70 EO 106 ) acts as a soft template to guide the mesoporous structure) by taking advantage of resol (phenol/formaldehyde) as carbon source, dicyandiamide as nitrogen source, and cobalt nitrate as cobalt source. We have optimized the performance of Co/Co 3 O 4 /NHPC composite base on the contents of Co/Co 3 O 4 in composite. 0.6-Co/Co 3 O 4 /NHPC (0.6 g cobalt nitrate in precursor solution) demonstrates a high discharge capacity (1823 mAh g −1 after 200 cycles at 0.2 A g −1 ), excellent cycling stability, and high-rate capability (1313/1056/576 mAh g −1 after 500 cycles at 2/5/10 A g −1 ). This outstanding LIB anode performance can be attributed to the hierarchically ordered porous carbon that could effectively provide rapid diffusion path way for electrolyte and metallic Co that could accelerate the transmission of electrons.