Ultrathin Mesoporous Co₃O₄ Nanosheet Arrays for High-Performance Lithium-Ion Batteries

Transition metal oxides, such as Co₃O₄, have attracted great attention for lithium-ion batteries (LIBs) due to their high theoretical capacity and satisfactory chemical stability. However, the slow kinetics of Li-ion and electron transport as well as poor cycling stability still largely restrains their applications. Here, we report the rational design of well-defined mesoporous ultrathin Co₃O₄ nanosheet arrays (NSAs) by topological transformation of layered double hydroxides nanosheet arrays (NSAs), which demonstrate significantly enhanced performance as anode for LIBs. The as-obtained Co₃O₄ NSAs with suitable thickness and abundant mesopores show excellent electrochemistry performance for LIBs, giving a high specific charge capacity of 2019.6 mAh g^-1 at 0.1 A g^-1, a good rate capability, and a remarkable cycling stability (1576.9 mAh g^-1 after the 80th cycle), which is much superior to that of Co₃O₄ with thicker or thinner nanosheets as well as to that of the reported results. This facile strategy may be extended to the synthesis of other transition metal oxide NSAs, which can be potentially used in energy storage and conversion devices.