Single Ion Conducting Hairy Nanoparticle Additive to Improve Cycling Stability of Solid Polymer Electrolytes

The development of a solid electrolyte that can impededendritegrowth while still maintaining an appropriate level of conductivityis essential for improving performance of solid-state Li-ion battery.In this paper, we report the synthesis of single Li-ion conductinghairy nanoparticle (NP) materials that improved the cycling stabilityof lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-doped poly(ethyleneoxide) (PEO) solid electrolyte without significant reduction in conductivity.To unveil mechanisms leading to improved cycling stability, severalcharacterization techniques including broadband dielectric spectroscopy,differential scanning calorimetry, small angle X-ray scattering, transmissionelectron microscopy, and shear rheology were used to study propertiesof polymer composites (PC) with added hairy NPs. It was found thathairy NPs influenced the Li/electrolyte interface and improved mechanicalproperties of bulk composites, all of which contributed to homogenousLi plating and stripping. The improved performance has been foundin composites with concentrations of 4.8 and 9.1 weight % of addedhairy NPs, which enabled Li cycling stability at 0.2 mA cm(-2) critical current density (>300 h) that was otherwise not possiblein either PEO-LiTFSI alone or PEO-LiTFSI composites containing a polymeridentical to that attached to hairy NPs. Based on the discovered abilityof hairy NP to influence bulk and interfacial properties of solidelectrolyte, their use as additives is expected to be equally effectivein reducing dendrite formation in other electrolytes relevant forthe design of solid-state battery.