Hierarchically mesoporous carbon nanofiber/Mn3O4 coaxial nanocables as anodes in lithium ion batteries

Abstract Carbon nanofiber/Mn 3 O 4 (CNF/Mn 3 O 4 ) coaxial nanocables with a three-dimensional (3D) structure are prepared for lithium ion batteries by electrophoretic deposition on an electrospun CNF cathode followed by heat treatment in air. The bark-like Mn 3 O 4 shell with a thickness of 30 nm surrounds the CNFs with a diameter of 200 nm; this hierarchically mesoporous Mn 3 O 4 shell consisted of interconnected nanoparticles grows radially toward the CNF core when viewed from the cross-section of the coaxial cables. The charge transfer resistance of the CNF/Mn 3 O 4 is much smaller than that of the Mn 3 O 4 powder, because of (i) the abundant inner spaces provided via the formation of the 3D coaxial core/shell nanocables, (ii) the high electric pathway for the Mn 3 O 4 nanoparticles attained with the 1D CNFs, and (iii) the structural stability obtained through the cushioning effect created by the CNF/Mn 3 O 4 coaxial morphology. These unique characteristics contribute to achieving a high capacity, excellent cyclic stability, and good rate capability. The CNF/Mn 3 O 4 nanocables deliver an initial capacity of 1690 mAh g −1 at a current density of 100  mA g −1 and maintain a high reversible capacity of 760 mAh g −1 even after 50 charge–discharge cycles without showing any obvious decay.