High-Performance V₂C MXene/Bilayered V₂O₅ Asymmetric Aqueous Supercapacitors

Two-dimensional transition metal carbides and nitrides (MXenes) have shown great potential in electrochemical energy storage applications. Their high electrical conductivity coupled with surface redox reactions make them suitable candidates for high-rate pseudocapacitive energy storage. However, MXene supercapacitors often exhibit a limited voltage at higher anodic potentials due to possible oxidation. One of the possible strategies to expand their voltage is by pairing them with suitable candidates such as oxides to design asymmetric supercapacitors. Among them, lithium intercalated bilayered V₂O₅ (Li-V₂O₅) is one of the promising candidates thanks to its high capacity and improved structural stability. In this study, we have explored free-standing films of lithium intercalated V₂C MXene (Li-V₂C) as negative electrode with Li-V₂O₅-CNT as positive electrode in aqueous LiCl electrolyte. This results in an electrochemically stable 2 V supercapacitor with high energy density and good cycling stability. The work highlights that MXenes, beyond Ti₃C₂, have great possibilities in electrochemical energy storage applications.