Metal-Ion-Intercalated MXene for Enhanced Capacitance in Supercapacitors

MXenes are high-performance pseudocapacitive materials known for their excellent conductivity, large surface area and fast redox reactions occurring at the surface. Despite these advantages, their practical application is hindered by the tendency of MXene nanosheets to aggregate and restack, which significantly compromises cycling stability. In this work, post-delamination metal-ion intercalation was employed to successfully expand the interlayer spacing of Ti3C2 while simultaneously optimizing its surface functional groups. Benefiting from the enlarged interlayer spacing and improved surface chemistry, the Mn-intercalated MXene (Mn–MXene) delivers a high specific capacitance of 285 F g−1 at a scan rate of 10 mV s−1 in 1 M H2SO4 electrolyte, which represents a 26% enhancement compared with pristine Ti3C2. Notably, Mn–MXene exhibits nearly 100% capacitance retention after 3000 cycles.