Cobalt‐doped Cu₆Sn₅ lithium‐ion battery anodes with enhanced electrochemical properties

Abstract

Sn‐based lithium‐ion battery anodes show improved capacities over commercial carbon‐based anodes. Furthermore, their higher lithiation potentials reduce the risks of Li dendrite formation. A simple Cu6Sn5 fabrication method has been previously demonstrated, but the resultant anode shows a poor reversible capacity of 470 mAh g–1. This study investigates the effects of Co in modifying the microstructure, crystal structure and electrochemical properties of Cu6Sn5 to improve the electrochemical performances of the electrode. Significant enhancement in the electrochemical properties were obtained in the Co‐doped Cu6Sn5 electrodes, where a cycling capacity as high as 830 mAh g–1 was observed during the early cycles, and a 35% increase in capacity over the pristine electrode is retained over 50 cycles. In addition, the pristine electrode does not function at a current of 0.64 mA cm–2 and above, while the Co‐doped electrode can retain a capacity of 410 mAh g–1 at a current of 1.28 mA cm–2 (2.4C). Detailed characterization of the electrodes revealed that the improved electrochemical performances are due to the refined microstructure and a higher reaction voltage during the second stage of the lithiation reaction which promotes a deeper lithiation.

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

“…13,14 It is noteworthy that the structural integrity of Cu 6 Sn 5 is strong among the original Sn-Cu intermetallics and their lithium-inserted counterparts, while also providing costeffective high energy storage. 15,16 Furthermore, many methods are employed to fabricate Cu 6 Sn 5 alloys, such as electron beam evaporation deposition, 17 solution synthesis, 18,19 and electrodeposition, 20,21 of which electrodeposition is an efficient method for achieving large-scale manufacturing of alloy electrodes due to its high productivity, simple process, and relative costeffectiveness.…”

Crystal structure informed mesoscale deformation model for HCP Cu6Sn5 intermetallic compound

“…This suggests that the knowledge of the structure and properties of Cu 6 Sn 5 IMC can eventually help in the design of strong and reliable solder joints. Besides the electronic packaging sector, the Cu 6 Sn 5 IMC is known as a promising candidate materials for the electrode of the Lithium-ion battery [3].…”

“…Cu 6 Sn 5 IMC can exist in two forms of crystalline structures [4]. At temperatures below 186 • C [3], it has a monoclinic crystalline structure, and is referred to as η ′ -Cu 6 Sn 5 . However, for temperatures higher than 186 • C, it undergoes a structural transformation to have a hexagonal closed packed structure [5], [6].…”