CO2-converted carbon nanotubes produced from molten salt electrolytes process for application of eco-friendly sustainable anode for sodium ion batteries

Abstract

CO₂-converted carbon nanotube (CNT) has been synthesized from industrial carbon dioxide emissions using a molten salt electrochemical process for an eco-friendly sustainable anode of sodium ion batteries (SIBs). The synthesized CNT have diameters ranging from 10 to 100 nm, and they combine with hard carbon (HC) to serve as SIB anode material. The synthesized CNT has the following roles: increasing the electrical conductivity of anode material, improving charge-discharge cycle stability, and enhancing sodium ion storage. We integrate these CNT into hard carbon by varying CNT contents, denoted as HC_xCNT(M), where x represents the weight of the CNT. So, the HC_5CNT(M) anode works better in half-cell SIBs, being able to handle different charging rates and reaching a maximum specific capacity of 256.7 mAh g⁻¹ at a 0.2C-rate. This material also displayed remarkable stability, maintaining a specific capacity of 99.48 mAh g⁻¹ at 1C-rate and the capacitive retention remained at 99.1 % after 800 cycles. The CO₂-converted CNT can improve electrical conductivity, specific capacity, and cycle stability, according to electrochemical analysis results. This innovative approach not only contributes to sustainable energy storage but also provides a valuable solution for reducing carbon emissions and repurposing industrial waste.