Copper nanofiber-networked cobalt oxide composites for high performance Li-ion batteries

Abstract

We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoO _x ). The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide. Compared to bare CoO _x thin-film (CoO _x TF) electrodes, the CuNFs@CoO _x electrodes exhibited a significant enhancement of rate performance by at least six-fold at an input current density of 3C-rate. Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network. Consequently, the CuNFs@CoO _x composite structure demonstrated here can be used as a promising high-performance electrode for Li-ion batteries.