Single-Phase Cu3SnS4 Nanoparticles for Robust High Capacity Lithium-Ion Battery Anodes

Abstract

With the evolution of Li‐ion batteries, they have been employed in many applications. However, high energy density and power density batteries are yet to be developed to meet the necessities at the application end. Sulfides are a good choice as anode material as they show a much higher specific capacity than conventional graphite anodes. But unfortunately, sulfide dissolution and polysulfide shuttling are big drawbacks for their operation. Herein, single phase ternary metal sulfide Cu3SnS4 (CTS) nanoparticles are synthesized with high Cu : Sn ratio and examined for application as Li‐ion battery anode. High specific capacities of 1082 mAh g−1 at 0.2 A g−1 and 440 mAh g−1 at a high rate of 3 A g−1 are realized with superior stability tested up to 950 cycles. Utilizing the CTS NPs can minimize the polysulfide dissolution. The high Cu : Sn ratio provides excess Cu atoms as the buffer matrix for volume expansion of Sn, leading to high stability and specific capacity. Compared to other reported Cu based mixed phase or composite ternary sulfide materials, the CTS NPs presented herein show a better performance. In a full cell device using LiCoO2 (LCO) as cathode, a good performance is achieved as well with an energy density of 405 Wh/Kg at 0.1 A g−1.