Unveiling highly ambient-stable multilayered 1T-MoS2 towards all-solid-state flexible supercapacitors

Abstract

Multilayered 1T-MoS₂ nanosheets are desired as an electrode material for supercapacitors. There is no effective way to synthesize pure, clean, highly ambient-stable, multilayered 1T-MoS₂ which results in the absence of intrinsic electrochemical storage mechanisms. Here, we report the intrinsic electrochemical storage mechanisms in three types of multilayered MoS₂ nanosheets including 2H-MoS₂, MoS₂-CTAB and highly ambient-stable pure 1T-MoS₂ nanosheets by magneto-hydrothermal synthesis. We reveal that layer spacing enhancement leads to an obvious improvement in specific capacitance (20 F g⁻¹ increased to 173 F g⁻¹) and enhanced hydrophilicity as well as metallic characteristics can further improve the specific capacitance (173 F g⁻¹ increased to 320 F g⁻¹). Furthermore, ex situ XRD tests show the expansion of interlayer spacing during charging of 1T-MoS₂ electrodes, suggesting the advantages of multilayered nanosheets used as electrodes for supercapacitors due to the enhanced capacitance from intercalation. All-solid-state flexible supercapacitors assembled with 1T-MoS₂ obtained by magneto-hydrothermal synthesis exhibit a high areal capacitance of 310 mF cm⁻² at 1 mA cm⁻², excellent flexibility and outstanding cycle stability, and the capacitance retention can remain above 97.3% and 84.1% after 10 000 and 30 000 cycles, respectively. These results unveil the electrochemical storage mechanisms in pure, clean, highly ambient-stable 1T-MoS₂ multilayered nanosheets, serving as promising supercapacitor electrodes for all-solid-state supercapacitors with excellent performance.