Hollow structured Sn-Co nanospheres by galvanic replacement reaction as high-performance anode for lithium ion batteries

Hollow Sn-Co nanospheres have been fabricated by galvanic replacement reaction. In particular, the hollow resultants with different shell thickness and void space can be obtained using sacrificial templates with different sizes. The structural evolution of Sn-Co hollow microspheres and structure changes during charge/discharge process were studied using XRD, SEM, and TEM. As an anodic material, the hollow resultants with thin shell and relatively large void space exhibited a good reversible capacity of 502 mAh g^?1 at a current density of 100 mA g^?1 and a coulomb efficiency over 99 % after 100 cycles. The contributions of the hollow structure and the inactive Co element to electrochemical performance were verified by galvanostatic charge/discharge cycling, electrochemical impedance spectroscope, and TEM measurements. A possible mechanism for hollow structure with different shell thickness to alleviate the volume change was proposed.