High‐rate metal‐free MXene microsupercapacitors on paper substrates
Han Xue, Po‐Han Huang, Lee‐Lun Lai, Yingchun Su, Axel Strömberg, Gaolong Cao, Yuzhu Fan, S. I. Khartsev, M. Göthelid, Yan‐Ting Sun, Jonas Weissenrieder, Kristinn B. Gylfason, Frank Niklaus, Jiantong Li
Abstract
Abstract MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors (MSCs). Despite its superior electrochemical performance, only a few studies have reported MXene‐based ultrahigh‐rate (>1000 mV s −1 ) on‐paper MSCs, mainly due to the reduced electrical conductance of MXene films deposited on paper. Herein, ultrahigh‐rate metal‐free on‐paper MSCs based on heterogeneous MXene/poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS)‐stack electrodes are fabricated through the combination of direct ink writing and femtosecond laser scribing. With a footprint area of only 20 mm 2 , the on‐paper MSCs exhibit excellent high‐rate capacitive behavior with an areal capacitance of 5.7 mF cm −2 and long cycle life (>95% capacitance retention after 10,000 cycles) at a high scan rate of 1000 mV s −1 , outperforming most of the present on‐paper MSCs. Furthermore, the heterogeneous MXene/PEDOT:PSS electrodes can interconnect individual MSCs into metal‐free on‐paper MSC arrays, which can also be simultaneously charged/discharged at 1000 mV s −1 , showing scalable capacitive performance. The heterogeneous MXene/PEDOT:PSS stacks are a promising electrode structure for on‐paper MSCs to serve as ultrafast miniaturized energy storage components for emerging paper electronics.