Antimony and its alloys have been intensively studied in recent years as high-capacity anode materials in alkali metal-ion based rechargeable batteries. It has a theoretical storage capacity of 660 mAh/g, which is almost twice as high as graphite (372 mAh/g) that is currently used in commercial lithium-ion batteries (LIB), and double that of hard carbon in emerging sodium-ion batteries. Recently, antimony-based anodes have been extended to include potassium-ion batteries. The range of antimony-alkali compounds that has been characterized is, however, considerably broader than just these two elements, and can include up to three alkali metal ions from group I, from lithium to cesium, with the number of intermediate compounds increasing as one moves down the group of the periodic table. In contrast to the more widely studied tin anodes, antimony shows good performance in conventional commercial carbonate-based electrolytes, making it a more suitable candidate to replace graphite in LIBs. Bismuth is isostructural with antimony and the elements have full mutual solid solubility above 200 °C. However, thermodynamic calculations suggest there is a miscibility gap below 140 °C. Like antimony, bismuth also alloys with up to three molar equivalents of alkali metals from lithium to cesium. Since bismuth is much more ductile than antimony, it makes the material less susceptible to fracture during electrochemical cycling with lithium, and there are several examples of bismuth addition to antimony improving the cycling stability relative to either element by itself. Although in-situ diffraction data of the individual elements during lithiation are available and show that A3Bi and A3Sb (A = Li, Na, K) are isostructural, no such data exist on binary Sb-Bi solid solutions. In addition, no ternary phase diagrams obtained via metallurgical routes have been reported. Solid-state nuclear magnetic resonance (NMR) spectroscopy is a highly sensitive method to interrogate local atomic chemical environments and is therefore suitable to study subtle compositional variations on short length scales (< 10 Å) in a multicomponent alloy. Such socalled incipien phase segrega ion can be de ec ed b NMR more readil han b o her techniques that represent an average long-range crystalline structure, as is the case for X-ray diffraction (XRD). The lithiation potential of antimony is approximately 200 mV more positive than that of bismuth, 8 indicating higher thermodynamic stability, which could result in the formation of Sb-rich clusters. Therefore, diffraction and NMR methods are complementary echniq es ha , oge her, pro ide a de ailed and n anced ie of a ma erial s s r c re. NMR also provides insightful information about dynamics, and the onset of ion dynamics within conductive materials, which is important information with regards to battery applications, and in particular rate-capability. In the present work, we study a series of ternary Li3SbxBi1-x compounds using XRD and NMR spectroscopy. The Li-rich alloys were synthesized using thermal annealing, ball milling, or a combination thereof, rather than electrochemical lithiation in order to more accurately control the Li-to-metal stoichiometry and eliminate any quantitative errors or additional NMR signals from Li salts formed by electrolyte decomposition. Antimony and bismuth show close-toideal solid solution behavior in binary alloys. Ternary Li3SbxBi1-x alloys show evidence of phase segregation for x = 0.25 and 0.50 (prior to annealing). A minority phase that is enriched in Sb is detected by NMR for x = 0.25. Our findings provide future directions for in-situ and operando diffraction experiments tracking phase transformations during lithiation of these binary metal Sb-Bi alloys.