Hierarchical CoNiO2 structures assembled from mesoporous nanosheets with tunable porosity and their application as lithium-ion battery electrodes

Mesoporous CoNiO2 hierarchical structures with various specific surface areas and pore size distributions were successfully synthesized by a hydrothermal method and the subsequent annealing process. Structural and compositional analysis indicated that the hierarchical structures were assembled from single-crystal nanosheets. The as-prepared sample when used as an anode material of Li-ion batteries delivered reasonable capacity, good cycling stability and rate capability. It has been found that the specific surface area and the pore nature of CoNiO2 hierarchical structures have a strong influence on their electrochemical performance. The optimal sample delivered a high reversible lithium storage capacity of similar to 449.3 mA h g(-1) after 50 cycles with high Coulombic efficiency at a current rate of 0.1 A g(-1), with good cycling stability and rate capability. It is believed that the improved electrochemical performance can be attributed to the mesoporous nature and the 3D assembled electrode structure. Therefore, such mesoporous hierarchical structures can be considered as attractive candidates as anode materials for LIBs.