Exploring lithium storage performance of two-dimensional Sb2Si2Te6-derived composites with carbon coating through polyacrylonitrile pyrolysis

Abstract

Two-dimensional materials have emerged as potential electrodes for lithium-ion storage, attributed to their adjustable band gap, abundant active sites, and efficient ion/electron transport properties. In this study, we synthesized Sb2Si2Te6 with layered structures via mechanical alloying and subsequent annealing, investigating its suitability as an anode material for lithium-ion batteries. We employed polyacrylonitrile (PAN) pyrolysis to encapsulate Sb2Si2Te6 in an amorphous carbon layer, resulting in the decomposition of Sb2Si2Te6 into Sb2Te3, Si and Te (denoted as Sb-Si-Te@C composite). This composite electrode exhibited excellent cycling stability, maintaining 505.6 mAh g−1 after 200 cycles (92.2% capacity retention), and enhanced rate performance compared to uncoated Sb2Si2Te6, which showed only 98.7 mAh g−1 after 200 cycles (33.1% capacity retention). Furthermore, the electrode expansion rate was significantly curtailed to 80.6% for Sb-Si-Te@C, compared to 174.3% for Sb2Si2Te6 after 100 cycles. This reduction indicates that the amorphous carbon layer enhances electron transfer during charging and discharging, effectively mitigating the electrode volume changes associated with cycling. These results underscore the potential of two-dimensional Sb2Si2Te6-derived composites as a promising anode material in lithium-ion batteries.