4D printing of MXene hydrogels for high-efficiency pseudocapacitive energy storage

2D material hydrogels have recently sparked tremendous interest owing to their potential in diverse applications. However, research on the emerging 2D MXene hydrogels is still in its infancy. Herein, we show a universal 4D printing technology for manufacturing MXene hydrogels with customizable geometries, which suits a family of MXenes such as Nb2CTx, Ti3C2Tx, and Mo2Ti2C3Tx. The obtained MXene hydrogels offer 3D porous architectures, large specific surface areas, high electrical conductivities, and satisfying mechanical properties. Consequently, ultrahigh capacitance (3.32 F cm(-2) (10 mV s(-1)) and 233 F g(-1) (10 V s(-1))) and mass loading/thickness-independent rate capabilities are achieved. The further 4D-printed Ti3C2Tx hydrogel micro-supercapacitors showcase great low-temperature tolerance (down to -20 degrees C) and deliver high energy and power densities up to 93 mu Wh cm(-2) and 7 mW cm(-2), respectively, surpassing most state-of-the-art devices. This work brings new insights into MXene hydrogel manufacturing and expands the range of their potential applications. 2D MXene hydrogels are promising for diverse applications. Here, the authors report a universal 4D printing technology to manufacture MXene hydrogels with customizable geometry, high conductivity, and efficient pseudocapacitive energy storage ability.

Automated summary

A universal 4D printing technology is developed to manufacture MXene hydrogels with customizable geometry, high conductivity, and efficient pseudocapacitive energy storage ability. The MXene hydrogels obtained possess 3D porous architectures, large specific surface areas, high electrical conductivities, and satisfying mechanical properties.