Exploring phosphate glass synthesis with LiMn2O4 cathode-active material alongside BaO as network modifier

The challenge of managing end-of-life Li + -ion battery (LIB) components is a growing concern in society demanding innovative solutions. In this work, the vitrification of LiMn 2 O 4 electrode-active material from LIBs is explored with phosphorus pentoxide alongside barium oxide as network modifier with a view toward upcycling. The glasses were successfully made by melting guided by the 60P 2 O 5 -(40 – x )BaO- x LiMn 2 O 4 formula with x = 5, 10, 15, 20 and 25 mol% with the 60P 2 O 5 -40BaO host synthesized as a reference. The characterizations performed included X-ray diffraction (XRD), density, differential scanning calorimetry (DSC), Fourier-transform infrared (FT-IR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy with emission decay measurements. The XRD data supported glass realization within the LiMn 2 O 4 concentration range up to 25 mol%. The densities decreased as LiMn 2 O 4 was added up to 20 mol% at the expense of BaO, whereas a slight density increase was observed for 25 mol% LiMn 2 O 4 . DSC measurements showed that the glass transition temperature overall tended to decrease, thus reflecting weaker glass networks. However, glass stability first improved up to 10 mol% LiMn 2 O 4 and declined thereafter. The FT-IR assessment indicated that network depolymerization took place with increasing LiMn 2 O 4 content ultimately making the glasses more prone to crystallization. Absorption spectroscopy showed progressively the presence of Mn 2+ and Mn 3+ ions consistent with LiMn 2 O 4 decomposition during melting. The PL evaluation exposed the red-emitting Mn 2+ ions wherein a PL quenching was observed above 5 mol% LiMn 2 O 4 , also revealed from the decay dynamics evaluation showing shorter Mn 2+ lifetimes. Overall, lower LiMn 2 O 4 loading appears more promising for further developing the glasses for light-emitting and energy-relevant applications.