Artificial Thiophdiyne Ultrathin Layer as an Enhanced Solid Electrolyte Interphase for the Aluminum Foil of Dual-Ion Batteries

In this study, we design a novel carbon-based material containing thiophene and acetylenic linkers as functional groups named thiophdiyne (Thi-Dy) and apply it as an ultrathin artificial protective layer for the commercially available aluminum (Al) foil of dual-ion batteries (DIBs). The Thi-Dy films can be grown easily and directly on the Al foil through a mild Glaser–Hay coupling reaction. The as-proposed thiophene and acetylenic linker functional groups in Thi-Dy layers act as energetic active sites for the effective fabrication of a stable hybrid solid electrolyte interphase (SEI) during the electrochemical process, which is revealed through the ex situ measurement. The Thi-Dy-enhanced SEI layer contributes to offer a more effective and regulated lithium intercalation and diffusion pathway and delay the pulverization and huge volume expansion of the Al–Li alloy during long cycles, which are confirmed by the improvement on the cyclic stability of DIBs. Those studies are expected to provide novel thiophene-containing functional materials and mass-produced surface modification approach for metal anode protection, which will promote the research for the next-generation rechargeable battery.