Multifunctional Copolymer Dispersants in High Solid Content Cathode Slurries: From Viscosity Reduction to Interfacial Stabilization and Improved Lithium Transport

Abstract A broad molecular weight distribution of one random copolymer (PBMP) dispersant is designed with multifunctional groups, which is expected to significantly improve the dispersion stability of LiFePO 4 (LFP) slurries as a result of the synergistic interactions between steric hindrance, surface adsorption, and electrostatic repulsion among LFP particles. The LFP slurry with a superior high solid content (62 wt.%) is experimentally demonstrated at a tiny amount of 0.25 wt.% PBMP, the viscosity of LFP slurry is reduced by 74.6% accompanied by a significant decrease of both zeta potential from −7.4 to −22.7 mV. The as‐fabricated high‐mass‐loading PBMP electrodes exhibit that the peeling strength is enhanced six times between the active layer and the current collector. Additionally, the strong interactions are theoretically inferred between the functional groups of PBMP and Li atoms within both LFP slabs , possibly resulting in reconfiguring the electronic distribution on LFP surfaces, accelerating the redox reactions within LFP electrodes, and optimizing Li + transport pathways. As such, PBMP electrodes can achieve 82.2 ± 6.2% capacity retention after 200 cycles at 1.0 C. This strategy therefore provides an innovative insight to regulate the interfacial stability of high‐mass‐loading electrodes and can be extended to the practical engineering application of lithium‐ion batteries.