Exploring the synergistic effects of lanthanum on sludge dewatering and carbonization for enhanced performance in lithium-sulfur batteries

Sludge based activated carbon (SBAC) has been widely studied due to its large specific surface area and affordability. Further research is required to improve the high-value resource utilization value of SBAC. This study evaluated the complex interaction between sludge EPS and LaCl₃ (La(III)). It also explored the enhanced sludge dewatering effect of La(III) and the innovative reuse of La(III) loaded SBAC (La@SBAC) in lithium sulfur (Li[sbnd]S) batteries. Research has shown that there is a significant interaction between La(III) and EPS, La(III) binds preferentially to EPS components in the order of polysaccharides > proteins > humic acid, consistent with their respective response degrees. La(III) favors binding to protein secondary structures in the sequence β-turn > α-helix > random coil > β-sheet. The binding of La (III) to EPS macromolecules altered its conformation, enhanced the hydrophobicity of EPS, and significantly improved the sludge dewatering performance. Simultaneously, the interaction between EPS and La(III) facilitated a substantial loading of La(III) onto the SBAC. Cleverly, La(III) modified SBAC was repurposed as a separator for Li[sbnd]S batteries, increasing conductivity while serving as an effective barrier to mitigate the polysulfide shuttle effect. This modification led to improved specific discharge capacity and superior long-term cycling performance. This study introduces an innovative method that simultaneously boosts the efficiency of sludge dewatering while facilitating the high-value reuse of sludge resources.