(Invited) Solid-State Chemistries Stable with High-Energy Cathodes for Lithium-Ion Batteries

Abstract

The continued improvement in operating time and lifetime of electric vehicles and portable electronic devices requires higher energy density lithium ion batteries. The energy density of lithium-ion batteries can be increased by implementing high-voltage cathodes, but these cathodes are reactive and unstable during cycling with the electrolyte. To design coatings or solid electrolytes that can stabilize these cathodes, an understanding of how different chemistries interact with high-voltage cathodes is critically needed. We systematically evaluate the thermodynamic stability of a broad range of solid-state chemistries with common cathodes (1). A materials trade-off is found in that materials stable with lithiated cathodes are often unstable with delithiated cathodes, which limits the possible choice of materials stable throughout the cycling voltage. These computational findings reaffirm previously demonstrated coating and solid electrolyte chemistries and suggest that several new chemistries, including lithium phosphates and lithium ternary fluorides, are promising solid-state chemistries stable with high-voltage cathodes. Our study provides guiding principles for designing coating and solid electrolyte materials with long-term stability with high-voltage cathodes for lithium-ion batteries.(1) Nolan et al., ACS Energy Lett. 2019, 4, 2444–2451