Industry‐Scale and Environmentally Stable Ti3C2Tx MXene Based Film for Flexible Energy Storage Devices

Abstract MXenes, 2D transition metal carbides, and nitrides have attracted tremendous interest because of their metallic conductivity, solution processability, and excellent merits in energy storage and other applications. However, the pristine MXene films often suffer from poor ambient stability and mechanical properties that stem from their polar terminal groups and weak interlayer interactions. Here, a heteroatom doping strategy is developed to tailor the surface functionalities of MXene, followed by the addition of large‐sized reduced graphene oxide (rGO) as conductive additives to achieve a scalable production of S, N‐MXene/rGO (SNMG‐40) hybrid film with high mechanical strength ( ≈ 45 MPa) and energy storage properties (698.5 F cm −3 ). Notably, the SNMG‐40 film also demonstrates long‐term cycling stability ( ≈ 98% capacitance retention after 30 000 cycles), which can be maintained under ambient condition or immersed in H 2 SO 4 electrolyte for more than 100 days. The asymmetric supercapacitor (aMGSC) based on SNMG‐40 film shows an ultrahigh energy density of 22.3 Wh kg −1 , which is much higher than those previously reported MXene‐based materials. Moreover, the aMGSC also provides excellent mechanical durability under different deformation conditions. Thus, this strategy makes MXene materials more competitive for real‐world applications such as flexible electronics and electromagnetic interference shielding.