Effects of nitrogen doping on lithium polysulfide anchoring by activated carbon derived from palm kernel shell

The dissolution of intermediate lithium polysulfide within the electrolyte presents a significant challenge in lithium-sulfur batteries (Li–S). While an increasing number of recent studies on Li–S are focused on using activated carbon (AC) cathodes due to their strong affinity to lithium polysulfide, there still has been limited investigation into the quantitative adsorption of lithium polysulfide across various ratios of urea doping with AC. This study thus aims to quantitatively study the polysulfide adsorption capabilities of biomass-based carbon material activated by KOH and doped with urea. The correlation between N-doped surface morphology and lithium polysulfide in the AC was thoroughly investigated. The results indicate that increasing the urea ratio improves AC’s porosity and enhances the lithium polysulfide adsorption. AC prepared with the highest biomass: urea ratio of 1:3 in this study exhibits the most remarkable adsorption uptake capacity of 12.94 mmol/g. This excellent adsorption performance is attributed to the synergistic effect of well-developed porosity (BET surface area of 1902.99 cm 2 /g and a pore volume of 0.92 cm 3 /g) and high nitrogen functionalization on the carbon surface, contributing to the formation of physical and chemical bonds between polarized lithium polysulfide and the carbon matrix that enhances the adsorption process.