context: Herein, with the aid of an electrochemistry-driven method, Fe ions were pre-intercalated into multilayered Ti3C2Tx (ML Ti3C2Tx) using cyclic voltammetry (CV) technology. Systemic characterization of the interlayer environment was conducted. The location of Fe ions was analyzed, combined with DFT simulations. The EMIm+ storage abilities of the Fe pre-intercalated MXene were confirmed using a dual-ion energy storage system including a graphite cathode. Meanwhile, the intercalation behavior of EMIm+ was studied via ex situ XRD and XPS. The complex relationship between the interlayer, EMIm+, and confined Fe ions was investigated.
answer: graphite