Rational design of binder-free Sn film anode for lithium ion batteries

Substantial efforts have been made to improve the electrochemical properties of tin-based materials as substitute for traditional graphite anode materials. However, the large volume expansion of metallic tin hampers its development. In this paper, we design a binder-free anode configuration with Sn-carbon based materials (Cu@C/Sn). As-grown carbon spheres, sandwiched between Sn film and Cu grid, were utilized as a buffer layer to cushion the volume expansion occurred in the Sn film during charging and discharging processes. The Cu@C/Sn exhibits excellent capacity retention after 150 cycles with a nearly 100% columbic efficiency. It delivers a specific capacity of 432.6 mAh/g at the 100 mA/g, several times higher than that in the Cu@Sn anode. Our results reveal that the buffer layer of carbon spheres plays an important role to enhance the electrochemical performance of Cu@C/Sn.