Citric acid and plasma treated MoS2 for high-performance supercapacitors

Abstract

Plasma treatment of molybdenum disulfide (MoS₂) presents several advantages that enhance its performance and broaden its applications. Firstly, the plasma bombardment effectively removes dirt from the surface of MoS₂, exposing a pristine surface. Secondly, the treatment induces functional modifications of MoS₂, including processes such as nitrification and fluorination. Lastly, plasma treatment can alter the crystal structure and morphology of MoS₂. Herein, we achieve high electrochemical performance in citric acid-modified MoS₂ (MoS₂/C) through plasma treatment. Additionally, MoS₂/C shows varied supercapacitor performance with plasma treatment at different power levels. The treatment results in increased nitrogen doping and reduced surface oxygen content, which enhances the availability of electrons in the Mo 3d orbitals, thereby improving the conductivity and overall electrochemical performance. Notably, MoS₂/C treated with 200 W power plasma exhibits a high specific capacitance of 202 F g⁻¹ at 1 A g⁻¹, along with an impressive capacity retention of 93.75% after 8000 cycles at 20 A g⁻¹. Moreover, symmetrical supercapacitor devices assembled with two MoS₂/C-200 W electrodes on carbon cloths further demonstrate excellent supercapacitor performance. This work illustrates that plasma treatment technology provides significant advantages, positioning it as a promising material in the field of energy storage.