(652a) Spherical Agglomeration of Battery Materials: Mechanistic Understanding and Hollow Agglomerate Formation

Battery electrode microstructure is known to strongly influence both capacity and rate capability for lithium ion batteries. High tortuosity and disrupted conductivity networks limit ion and electron transport in batteries, and therefore control of electrode microstructure can improve high-performance electrodes.

Spherical agglomeration is an in-suspension agglomeration technique, which uses the addition of immiscible fluids to generate agglomerate structures with desired particle attributes. In this study, the spherical agglomeration technique is manipulated to produce hollow co-agglomerated particulate structures for application in battery electrode manufacture. In particular, the rate limiting particle immersion mechanism is exploited, which allows for the tailoring of particle structure.

High value characterisation techniques such as SEM, XRCT and particle size measurements are used to examine agglomerate structure, and to provide insight into the controlling mechanisms of formation. A thermodynamic analysis found that interfacial energy gradient is seen to be pivotal for particle transfer between immiscible fluids, and thus successful spherical agglomerate systems. A regime map is proposed which aids in the generation of novel agglomerate structures, based on a modified capillary number describing the ratio of viscous dissipation to the work of particle transfer.

Agglomeration of battery electrode materials has many potential promising benefits including improved homogeneity, reduced carbon migration and improved particle handling, whilst the process can operate at ambient conditions. The results of this research offer a potential route for the development of intentionally designed high-performance battery electrodes, and demonstrates the ability to create hollow particulate structures using advanced manufacturing techniques. The process also shows great promise for other industries such as pharmaceuticals and agrichemicals.