Dealloying approach for the rapid synthesis of Sn-based intermetallic electrodes for lithium-ion batteries

Abstract Sn-based alloys are potential candidates for replacing graphite as the anode material in Li-ion batteries (LIBs) due to their high theoretical electrochemical capacities. The second element in Sn alloys can be redox-active, contributing to the total electrochemical capacity, or nonactive, acting as a buffer for the volume change of the electrode caused by Li insertion/removal. In this study, we provide a straightforward technique for synthesizing Ni3Sn2 and Cu6Sn5 intermetallic materials by chemically dealloying ternary Al-Cu-Sn and Al-Ni-Sn alloys. In these alloys, Ni and Cu do not form any alloys with Li. Cu6Sn5 has a second-cycle charge capacity of approximately 900 mA h g−1 in Li batteries at a current density of 0.1 A g−1, and the capacity subsequently decreases to 340 mA h g−1 after 100 cycles. Although the nanoporous Ni3Sn2 anode initially has a lower charge capacity of 371 mA h g−1, its cycling behavior becomes considerably more stable after 100 cycles, with a capacity of 347 mA h g−1 at the same current density. Despite the fact that the capacity of Ni3Sn2 is lower than that of Cu6Sn5 at current densities below 2 A g−1, it preserves a capacity of more than 150 mA h g−1 at current densities of 5 and 10 A g−1. This result may be explained by the consistent pore distribution of Ni3Sn2 and its particles' larger specific surface area of 19 m2 g−1, resulting in better electron and ion transport.