Fabrication of Hollow and Hierarchical CuO Micro–Nano Cubes Wrapped by Reduced Graphene Oxide as a Prospective Anode for SIBs
Jia Wen, Rong Jiang, Junyuan Huang, Yuan Xie, Le Ma, Xinyu Li, Yang Ren, Zhu Liu, Bowen Xiao, Xiaowei Zhou
Abstract
In this study, hollow and hierarchical CuO micro–nano cubes wrapped by reduced graphene oxide (H-CuO MNCs@rGO) were designed and successfully fabricated via a novel three-step wet-chemical method. Benefiting from its unique hollow and hierarchical micro–nano structures, H-CuO MNCs@rGO exhibited significantly enhanced electrochemical Na + storage performance when utilized as anode material for sodium-ion batteries (SIBs). Specifically, H-CuO MNCs@rGO demonstrated a specific capacity of 380.9 mAh g –1 in the initial reversible cycle and a capacity retention of 218.9 mAh g –1 after 150 cycles at a current density of 300 mA g –1 . Furthermore, through the dominant pseudocapacitive behavior, an optimized rate capability of 221.2 mAh g –1 at 800 mA g –1 can be obtained for H-CuO MNCs@rGO. The comprehensive Na + storage properties of H-CuO MNCs@rGO obviously exceeded those of hollow CuO cubes (H-CuO MNCs) and bulk CuO anodes. Such enhanced Na + storage performances of H-CuO MNCs@rGO can be attributed to its reasonable hollow and hierarchical micro–nano structures, which provide abundant redox active sites, shorten Na + migration pathway, buffer volume expansion, and improve electronic/ionic conductivity during sodiation/desodiation process. Our strategy provides a facile and innovative approach for the design of CuO with rational micro–nano structure as a high-performance anode for SIBs, which would also be a guiding way for tailoring transition metal oxides in other scalable and functional applications.