title: Optimization of multicomponent aqueous suspensions of lithium iron phosphate (LiFePO4) nanoparticles and carbon black for lithium-ion battery cathodes.
abstract: Addition of polyethyleneimine (PEI) to aqueous LiFePO4 nanoparticle suspensions improves stability and reduces agglomerate size, which is beneficial to lithium-ion battery cathode manufacturing. This research examines the effect of both PEI concentration and molecular weight (MW) on dispersing LiFePO4 and Super P C45 in multicomponent aqueous suspensions. It is demonstrated that the optimal conditions for obtaining stable suspensions with minimal agglomerate size are 1.5 wt% PEI with MW=2000 g mol(-1) and 5.0 wt% PEI with MW=10,000 g mol(-1) for LiFePO4 and Super P C45, respectively. The mixing sequence also affects rheological properties of these suspensions. It is found that dispersing the LiFePO4 and Super P C45 separately yielded suspensions with superior properties (Newtonian rheological behavior, smaller agglomerate size, improved settling, etc.). In particular, dispersing the LiFePO4 prior to the Super P C45 when making the final multicomponent suspension is found to be beneficial, which was evidenced by higher half-cell discharge capacity.
authors.affiliation: Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. lij4@ornl.gov
authors.forename: Jianlin
authors.initials: J
authors.lastname: Li
authors.forename: Beth L
authors.initials: BL
authors.lastname: Armstrong
authors.forename: Claus
authors.initials: C
authors.lastname: Daniel
authors.forename: Jim
authors.initials: J
authors.lastname: Kiggans
authors.forename: David L
authors.initials: DL
authors.lastname: Wood