Porous Core-Shell CuCo₂ S₄ Nanospheres as Anode Material for Enhanced Lithium-Ion Batteries

Porous core-shell CuCo₂ S₄ nanospheres that exhibit a large specific surface area, sufficient inner space, and a nanoporous shell were synthesized through a facile solvothermal method. The diameter of the core-shell CuCo₂ S₄ nanospheres is approximately 800 nm" the radius of the core is about 265 nm and the thickness of the shell are approximately 45 nm, respectively. On the basis of the experimental results, the formation mechanism of the core-shell structure is also discussed. These CuCo₂ S₄ nanospheres show excellent Li storage performance when used as anode material for lithium-ion batteries. This material delivers high reversible capacity of 773.7 mA h g^-1 after 1000 cycles at a current density of 1 A g^-1 and displays a stable capacity of 358.4 mA h g^-1 after 1000 cycles even at a higher current density of 10 A g^-1 . The excellent Li storage performance, in terms of high reversible capacity, cycling performance, and rate capability, can be attributed to the synergistic effects of both the core and shell during Li⁺ ion insertion/extraction processes.