High electrochemical performances of hierarchical hydrangea macrophylla like NiCo2O4 and NiCo2S4 as anode materials for Li-ion batteries

• Hierarchical NiCo2O4 is successfully fabricated.
• Hierarchical NiCo2S4 is prepared via sulfide anion exchange.
• The hierarchical NiCo2O4 and NiCo2S4 exhibit good electrochemical properties.

In this work, hierarchical hydrangea macrophylla like NiCo2O4 has been synthesized by solvothermal method followed by calcination treatment in air. By using Na2S as sulfur source, the NiCo2O4 is converted into NiCo2S4. Such hierarchical NiCo2O4 exhibits a high specific capacity and excellent cycling stability (928 mAh g−1 at a current density of 100 mA g−1 after 100 cycles). Even at high current density of 2000 mA g−1, the electrode still delivers a specific capacity of 371 mAh g−1 after 50 cycles. When the NiCo2S4 is used as anode materials for lithium-ion batteries, a high discharge capacity of 1204 mAh g−1 can be achieved. Meanwhile, the NiCo2S4 electrode displays good cycling stability and rate capability. The excellent electrochemical performances can be attributed to the unique porous structure, which can effectively reduce the diffusion length for lithium ions and electrons, and alleviate volume expansion during the charge-discharge processes.

Mesoporous hydrangea macrophylla like NiCo2O4 and NiCo2S4 have been fabricated, which present excellent electrochemical performances as anode materials for Li-ion batteries.Figure optionsDownload as PowerPoint slide