Defect-engineered sulfur-vacancy-assisted MoS2 toward high-performance flexible supercapacitors

초록

The limited electrochemical activity and poor electrical conductivity of pristine 2H-MoS2 hinder its application as a high-performance supercapacitor (SC) electrode. Herein, we investigate whether controlled engineering of sulfur (S) vacancies can enhance the electrochemical performance of MoS2. S-vacancy-enriched 2H-MoS2 micro-/ nanoparticles were synthesized via a facile NaBH4-assisted coprecipitation method by systematically varying the reduction time (0-45 min) to regulate the defect concentration. Structural, morphological, and spectroscopic analyses confirmed successful sulfur vacancy generation, with the optimized MoS2-SV30 sample exhibiting a highly disordered, poorly crystalline structure and abundant vacancy-rich active sites. The optimized sulfur vacancy concentration enhanced charge transport and increased the number of electrochemically active sites, enabling a high specific capacitance of 512 F g-1 at 0.7 A g-1 with 98.5% capacitance retention after 10,000 cycles at 10 A g-1. A flexible asymmetric SC assembled using MoS2-SV30 and MnO2 achieved an areal energy density of 64.7 mu Wh cm-2 at 1000 mu W cm-2 and retained 84% of its capacitance after 5000 cycles. This work demonstrates that systematic sulfur vacancy optimization is an effective strategy for developing highperformance MoS2-based SC electrodes.

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