Development of Heteroatomic Constant Potential Method with Application to MXene-Based Supercapacitors

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Electrode complexity in electrochemical research is increasing.
• Accurate modeling of charge distribution in heteroatomic electrodes is challenging.
• Existing constant potential methods (CPM) may not fully capture elemental variations.

Purpose of the Study:

• To introduce a novel heteroatomic constant potential method (HCPM) for modeling charges in complex electrode materials.
• To address the limitations of conventional CPM in handling diverse elemental compositions.
• To improve the accuracy of charge distribution and response predictions in electrochemical systems.

Main Methods:

• Developed the heteroatomic constant potential method (HCPM) with minimal added parameters.
• Fitted HCPM parameters to density functional theory (DFT) partial charge predictions using derivative-free optimization.
• Performed molecular dynamics simulations comparing HCPM and conventional CPM for MXene electrodes with Li-TFSI/AN electrolytes.

Main Results:

• HCPM and CPM showed similar overall charge storage.
• HCPM provided a more reliable depiction of electrode atom charge distribution and response compared to CPM.
• HCPM simulations indicated increased cationic attraction to the MXene surface.

Conclusions:

• Elemental composition significantly influences electrode performance in electrochemical systems.
• HCPM offers a flexible and accurate approach for studying diverse heteroatomic electrodes.
• The method is applicable to various materials including MXenes, 2D materials, MOFs, and doped carbon electrodes.