Dealloying-Derived Nanoporous Cu₆Sn₅ Alloy as Stable Anode Materials for Lithium-Ion Batteries

The volume expansion during Li ion insertion/extraction remains an obstacle for the application of Sn-based anode in lithium ion-batteries. Herein, the nanoporous (np) Cu₆Sn₅ alloy and Cu₆Sn₅/Sn composite were applied as a lithium-ion battery anode. The as-dealloyed np-Cu₆Sn₅ has an ultrafine ligament size of 40 nm and a high BET-specific area of 15.9 m² g^-1. The anode shows an initial discharge capacity as high as 1200 mA h g^-1, and it remains a capacity of higher than 600 mA h g^-1 for the initial five cycles at 0.1 A g^-1. After 100 cycles, the anode maintains a stable capacity higher than 200 mA h g^-1 for at least 350 cycles, with outstanding Coulombic efficiency. The ex situ XRD patterns reveal the reverse phase transformation between Cu₆Sn₅ and Li₂CuSn. The Cu₆Sn₅/Sn composite presents a similar cycling performance with a slightly inferior rate performance compared to np-Cu₆Sn₅. The study demonstrates that dealloyed nanoporous Cu₆Sn₅ alloy could be a promising candidate for lithium-ion batteries.