Suppression of Transition Metal Dissolution in Mn-Rich Layered Oxide Cathodes with Graphene Nanocomposite Dry Coatings

The growing demand for lithium-ion batteries (LIBs) and the reliance on scarce metals in cathode active materials (CAMs) have prompted a search for sustainable alternatives. However, the performance of Mn-rich CAMs formulated with less Co suffer from transition metal dissolution (TMD). TMD can be suppressed by applying a thin film of carbon or oxide to the CAM but the assumed need for a continuous film necessitates bottom-up coating methods. This has been a challenge for LIB production as well as limiting material choices. Here we show that particulate coatings can also suppress TMD, allowing for scalable, material-independent, dry coating methods. Dry coating the Mn-rich CAM surfaces with graphene encapsulated nanoparticles (GEN) (1 wt%) suppresses TMD while nearly doubling the cycle life and improving rate capacities up to 42% under stressful conditions. The ability to suppress TMD is attributed to the unique chemical and electronic properties of the GEN produced by plasma enhanced chemical vapor deposition. The method is general and could provide a scalable path to CAM with less Co.