High-Mass-Loading Porous Ti₃C₂T_x Films for Ultrahigh-Rate Pseudocapacitors

Mass production of ordered and porous three-dimensional (3D) electrodes is a crucial prerequisite for practical energy storage devices. MXenes have drawn considerable attention as pseudocapacitive materials for outstanding electric conductivity and surface redox reactions; however, they face challenges for achieving 3D porous architectures especially at high mass loadings. Herein we propose a reduced-repulsion freeze-casting assembly concept via interlayer interaction engineering for constructing 3D porous Ti3C2Tx films, wherein interlayer repulsion is minimized via less electronegative functional groups and charge screening effect based on quantum calculations. 3D Ti3C2Tx films deliver a capacitance of 207.9 F g–1 at 10 V s–1, which demonstrates 58.6% capacitance retention with a 1000-fold scan rate increase. The capacitive performance is almost independent of electrode mass loading up to 16.18 mg cm–2, exhibiting ultrahigh areal capacitance of 3731 mF cm–2 and energy density of 336.7 μWh cm–2.