Towards Cs-ion supercapacitors: Cs intercalation in polymorph MoS₂ as a model 2D electrode material.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Intercalation of alkali metals (Li+, Na+, K+) is a known strategy to improve energy storage in layered 2D materials.
• Research has primarily focused on Li+ and Na+ intercalation, with K+ being a recent addition.
• Cesium (Cs+) intercalation has not been explored for batteries or supercapacitors despite the high solubility of Cs salts.

Purpose of the Study:

• To investigate the effect of Cs+ intercalation in molybdenum disulfide (MoS2) as a model 2D material.
• To evaluate the potential of Cs+-intercalated MoS2 as a supercapacitor electrode material.
• To explore the impact of Cs+ on MoS2 phase stability and electrical conductivity.

Main Methods:

• Experimental intercalation of Cs+ into MoS2.
• Phase analysis of MoS2 before and after Cs+ intercalation.
• Electrical conductivity measurements of different MoS2 phases.
• Quantum capacitance (CQ) measurements for Cs+-intercalated MoS2 and doped graphene.

Main Results:

• Cs+ intercalation stabilizes the metastable 1T phase of MoS2.
• Cs+ intercalation significantly increases the electrical conductivity of both 2H and 3R MoS2 phases.
• Cs+-intercalated 1T MoS2 exhibits higher quantum capacitance (CQ) compared to doped graphene.

Conclusions:

• Cs+ intercalation is a highly effective method for enhancing the energy storage capabilities of MoS2.
• The improved conductivity and phase stabilization contribute to superior supercapacitor electrode performance.
• Cs+-intercalated MoS2 presents a promising alternative to conventional electrode materials like doped graphene.