Realizing stable lithium and sodium storage with high areal capacity using novel nanosheet-assembled compact CaV4O9 microflowers

Abstract

Realizing stable cycling performance with high areal capacity is a great challenge for metal-ion battery anodes. Achieveing high areal capacity generally requires the electrode in a high active loading with increased electrode thickness, which is not beneficial to the cycling stability. In this work, novel nanosheet-assembled compact CaV4O9 microflowers are firstly synthesized through a facile method, which exhibit both high areal capacity and stable cycling performance at high mass loadings. The compact microflower structure leads to an increased tap density of the electrode materials, benefiting to reduce the anode thickness at high mass loadings. Meanwhile, the assembled nanosheets maintain the nano-effects of the active materials for favorable electrochemical reactions. These merits together with the intrinsic superior electrochemical properties of CaV4O9, result in the outstanding electrochemical performance. When used as Li-ion battery anodes, a high areal capcity of ~2.5 mAh cm−2 at a high mass loading of 4.4 mg cm−2 is obtained, and a stable cycling over 400 cycles with the areal capacity over 1.5 mAh cm−2 is demonstrated. Besides, the superior electrochemical performance at high mass loadings is also observed for Na storage. These achievements may pave the way for constructing applicable high-capacity and stable anode materials in metal-ion batteries.