Interlayer Hydrogen‐Bonded Metal Porphyrin Frameworks/MXene Hybrid Film with High Capacitance for Flexible All‐Solid‐State Supercapacitors

Abstract 2D metal‐porphyrin frameworks (MPFs) are attractive for advanced energy storage devices. However, the inferior conductivity and low structural stability of MPFs seriously limit their application as flexible free‐standing electrodes with high performance. Here, for the first time, an interlayer hydrogen‐bonded MXene/MPFs film is proposed to overcome these disadvantages by intercalation of highly conductive MXene nanosheets into MPFs nanosheets via a vacuum‐assisted filtration technology. The alternant insertion of MXene and MPFs affords 3D interconnected “MPFs‐to‐MXene‐to‐MPFs” conductive networks to accelerate the ionic/electronic transport rates. Meanwhile, the interlayer hydrogen bonds (F···HO and O···HO) contribute a high chemical stability due to a favorable tolerance to volume change caused by phase separation and structural collapse during the charge/discharge process. The synergistic effect makes MXene/MPFs film deliver a capacitance of 326.1 F g −1 at 0.1 A g −1 , 1.64 F cm −2 at 1 mA cm −2 , 694.2 F cm −3 at 1 mA cm −3 and a durability of about 30 000 cycles. The flexible symmetric supercapacitor shows an areal capacitance of 408 mF cm −2 , areal energy density of 20.4 µW h cm −2 , and capacitance retention of 95.9% after 7000 cycles. This work paves an avenue for the further exploration of 2D MOFs in flexible energy storage devices.