Adsorption mechanism of sodium polysulfide clusters on selenium-doped Ti2CO2 MXenes for application in sodium-sulfur batteries

Trong Mai To — 2026-01-12

Room-temperature sodium-sulfur batteries show great potential for future energy storage systems; however, challenges such as the shuttle effect and poor conductivity hinder their practical application. The shuttle effect not only leads to energy loss but also diminishes the electrochemical performance of the batteries. The movement of these polysulfides can result in a gradual decrease in battery capacity, making it difficult to maintain consistent performance over time. Additionally, low conductivity can hinder charge transfer, slowing reaction kinetics and further reducing overall battery efficiency. One effective approach to address these issues is to use two-dimensional (2D) MXenes as electrode anchoring materials, which can help suppress the shuttle effect and enhance the electronic conductivity of sodium-sulfur batteries. This study investigates the effects of doping selenide atoms into 2D MXenes using first-principles methods to improve the stability and electronic properties of sodium-sulfur batteries. The selenide atoms are introduced into the termination layer to capture sodium polysulfide clusters. Our findings indicate that by doping with selenide atoms, the interaction between the Se-4p and S-3p orbitals enhances the ability of Ti₂CO₂ MXenes to adsorb Na₂S and Na₂S₂ clusters compared to the pristine systems. We provide a detailed discussion of the bonding mechanism between the Na₂S_x clusters and the selenide-doped MXenes. Furthermore, we highlight the differences in adsorption mechanisms between low-sulfur content (Na₂S, Na₂S₂, and Na₂S₄) and high-sulfur content (Na₂S₆ and Na₂S₈) clusters, focusing on charge transfers and electronic properties. The distinctive structure of MXenes allows them to interact effectively with polysulfides, which can suppress the shuttle effect, thereby preventing polysulfide migration and reducing energy loss. Moreover, the enhanced conductivity provided by MXenes facilitates improved charge transfer, leading to superior overall performance in sodium-sulfur batteries. Our results emphasize the critical role of selenide atoms in 2D MXene electrode materials, enhancing the adsorption mechanism of sodium polysulfides for their application in sodium-sulfur rechargeable batteries.

Impact of Fluorine content on the Stability and Electronic properties of Sodium Lithium Manganese Oxide Cathode materials for Sodium-ion batteries

Phuc An Nguyen — 2026-01-20

Sodium-ion batteries are emerging as a promising alternative to traditional rechargeable batteries, such as lithium-ion and lead-acid batteries. One of the most significant advantages of sodium-ion technology is that it utilizes materials that are not only cost-effective but also environmentally friendly. The raw materials needed to produce sodium-ion batteries are widely available, leading to reduced supply chain risks and potential price volatility often associated with lithium resources. Furthermore, the transition in energy storage mechanisms and manufacturing techniques from lithium-ion batteries is seamless since the two technologies facilitate a relatively smooth integration into existing production methods, which can lead to substantial cost savings for manufacturers. As the demand for energy storage continues to grow, the shift towards sodium-ion technology represents not just an innovation but also a practical move in battery production. Among the various cathode materials being researched for sodium-ion batteries, sodium lithium manganese oxides (NLM) have garnered attention for their potential. They exhibit good capacity and energy density; however, one of the critical challenges in their application is the Jahn-Teller distortion. This phenomenon occurs during cycling due to the changes in the valence state of manganese within the structure. As the battery operates, this distortion can lead to irreversible phase changes, compromising the structural integrity of the material and diminishing its capacity over time. To address these challenges, we investigate the role of fluorine content in enhancing the structural stability and electrochemical characteristics of (Co, F)-co-doped NLM cathode materials. By incorporating fluorine into the material's composition, we reveal that the effect of Jahn-Teller distortion can be mitigated. This modification not only helps preserve the capacity of the battery over multiple cycles but also improves the overall electrochemical performance of the cathodes. The results underscore the effectiveness of co-doping strategies, combining both cationic (like cobalt) and anionic (like fluorine) ions, to enhance the properties of electrode materials. This approach could hold the key to unlocking better performance in sodium-ion batteries, ultimately contributing to the development of next-generation energy storage solutions that are more efficient and sustainable. In summary, the advances in sodium-ion battery technology signal a significant step forward in energy storage systems. By tackling the limitations of existing materials and optimizing their composition, researchers are paving the way for viable alternatives to lithium-ion technology, thereby promoting a more sustainable and cost-effective energy future.

VNUHCM Journal of Engineering and Technology

Adsorption mechanism of sodium polysulfide clusters on selenium-doped Ti2CO2 MXenes for application in sodium-sulfur batteries

Impact of Fluorine content on the Stability and Electronic properties of Sodium Lithium Manganese Oxide Cathode materials for Sodium-ion batteries