Highly flexible, foldable carbon cloth/MXene/polyaniline/CoNi layered double hydroxide electrode for high-performance all solid-state supercapacitors

Abstract

Layered double hydroxide (LDH) has become one of the prospective electrode materials due to high specific area, good cycle stability and high power density. However, large internal resistance limits its application in energy storage. The introduction of materials with high electrical conductivity is expected to solve this problem. In here, carbon cloth/MXene/PANI/CoNi-LDH (CC/MXPACN) composites are fabricated by the electrodeposition of PANI and CoNi-LDH on the CC coated with MXene. The effects of electrodeposition time on the electrochemical performances are investigated in detail. The asymmetric supercapacitor is assembled with CC/MXPACN as the positive electrode and activated carbon (AC) as the negative electrode. The device has a 1.6 V voltage window. After 10,000 cycles at a current density of 5 A g−1, the capacitance retention rate is still 91 %. At the power density of 399.95 W kg−1, the energy density of 39.33 Wh kg−1 is provided. Even at the high power density of 2400.35 W kg−1, the energy density can still reach 27.27 Wh kg−1. The asymmetric device has high specific capacitance, long-term stability and good power density and energy density, which exhibit a huge potential in energy storage applications.