Assignment of 39K NMR signals for potassium–graphite intercalation compound KC8

Abstract

Abstract Potassium–graphite intercalation compounds (K–GICs) have potential applications in potassium-ion batteries. Although previous research has reported solid-state nuclear magnetic resonance (NMR) measurements on K–GICs, the assignment of their 39K NMR spectra remains unclear. In this study, we provide new insights into the 39K NMR spectral assignment for K–GICs and reveal that the state of the intercalated potassium ions varies even for compounds with the same composition.