Activating an MXene as a host for EMIm+ by electrochemistry-driven Fe-ion pre-intercalation

EMIm+, as a substitute for Li+, can solve the initial problems that accompany lithiation/delithiation processes on an anode. However, the larger size of EMIm+ limits the options when it comes to electrode materials. Herein, a multilayered Ti3C2Tx MXene was electrochemically pre-intercalated with Fe ions to achieve EMIm+ hosting abilities. As a result, a pre-intercalated MXene electrode exhibited enhanced EMIm+ transport and storage capabilities. When integrated with an EMIm+[PF6]− ionic liquid electrolyte, the assembled DIB provides an energy density of 76 W h kg−1 at a power density of 360 W kg−1, and 94.3% of the energy density is retained after 50 cycles. Compared with a pristine example, the Fe pre-intercalated Ti3C2Tx MXene showed a significant increase in electrochemical performance. Employing this approach to optimize layered materials may open up a new route for accurately tuning intercalated materials.