Carbon shell coated hollow NiCoSex composite as high-performance anode for lithium storage

Hollow NiCoSex (H-NiCoSex) nanospheres encapsulated with carbon shell were prepared via one-step easy solvothermal method followed by the carbon coating process. H-NiCoSex@C has large interior void with the uniform dimension around 350 nm and the thickness of carbon shell around 20–30 nm. Coupling with the large interior void as well as robust protective carbon shell, H-NiCoSex@C can retain the reversible capacity of 805.6 mAh·g−1 after 100 cycles at 200 mA·g−1. In particular, H-NiCoSex@C delivers large reversible capacity of 1532.2 mAh·g−1 upon cycling for 1000 loops at 1000 mA·g−1 with the capacity retention as high as 128.2% upon long period of activation. Even at the high rate of 3000 mA·g−1, its specific capacity still retains up to 659.3 mAh·g−1. The superior lithium storage performances for H-NiCoSex@C profit from its robust hollow core-shell structure as well as enhanced electrical conductivity and ion transport.