Electrochemical performance of Cu6Sn5 alloy anode materials for lithium-ion batteries fabricated by controlled electrodeposition

Abstract

Combining electrodeposition and heat treatment is an effective method to successfully fabricate Cu₆Sn₅ alloy materials, in which the S2 alloy electrode is electrodeposited at 1.2 A dm⁻² current density with uniform and compact morphology. The characterization results show that monoclinic η′-Cu₆Sn₅ and hexagonal η-Cu₆Sn₅ phases fabricated at the appropriate current density exhibit excellent electrochemical performance. The optimal Cu₆Sn₅ alloy anode material boasts not just a significantly high discharge specific capacity of 890.2 mA h g⁻¹ with an initial coulombic efficiency (ICE) of 73.96%, but also achieves an adequate discharge specific capacity of 287.1 after 50 cycles at 100 mA h g⁻¹. Moreover, the electrodeposited Cu₆Sn₅ alloy materials also possessed a lower transfer resistance of 42.45 Ω and an improved lithium-ion diffusion coefficient of 2.665 × 10⁻¹⁵ cm² s⁻¹ at the current density of 1.2 A dm⁻². Therefore, preparing the Cu₆Sn₅ alloy thin-film electrode could be a cost-effective and straightforward method by electrodeposition from cyanide-free plating baths to develop anode components suitable for lithium-ion battery applications.