Scalable spray-drying functionalization of carbon additives for enhanced performance of Li-ion batteries

An original and counterintuitive method for modifying the surface of carbon powders is proposed using diazonium chemistry. Diazonium salts are known to be sensitive to temperature and therefore must be carefully manipulated. However, if their degradation is forced but carefully controlled, it can be advantageous for achieving uniform surface modification. Here, we propose a spray-drying method in which a solution containing in-situ generated Cl − N 2 + -aryl-COOH salts are evaporated directly on the surface of carbon nanoparticles. The modified powders were analyzed using a set of analytical methods, which confirmed the enhanced grafting efficiency achieved by the spray-drying method compared with conventional methods. Carbon electrodes prepared with the aryl-COOH modified carbon exhibited a greatly reduced irreversible capacity than those made with pristine carbon. When incorporated as conductive additives in LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811)/Li cells, the modified carbons improved cycling stability, with the spray-dried carbon delivering the most significant enhancement. These results demonstrate that controlled diazonium decomposition during spray drying provides a rapid, scalable, and effective approach to functionalize carbon powders for high-performance Li-ion battery electrodes.