New oxide glass cathode materials for sustainable and high-energy density lithium batteries

Overview & Synopsis

As energy concerns grow and the society needs more sustainable and renewable energy sources, the ability to effectively store and retrieve energy is paramount. Currently, rechargeable lithium-ion batteries (LIB) seem to be one of the best alternatives to reduce our dependency on fossil fuels. LIB are made of cathodes materials based on polycrystalline oxides or polyanion compounds1. However, some of them have their performance limited by their crystalline structure where other compounds suffer from irreversible phase changes against cycling2. To overcome these key shortcomings, implement glasses or glass-ceramics as cathode materials seems to be an interesting approach. Glasses have a structure composed of more free volume, which can accept a large amount of lithium3 and easily accommodate structural changes upon lithium ions extraction/insertion4. Furthermore, glass production is scalable and commercially easier to implement than most of synthesis processes of conventional cathodes materials. In this study, various types of oxide glasses have been investigated as promising cathode materials for sustainable and high energy density lithium batteries. The influence of the nature of the transition metal (Fe, Mn, …) and the polyanion (PO4, BO3, SiO4) on the microstructural and electrical properties of the as-prepared glasses were examined. Electronic and ionic conductivities were measured by Electrochemical Impedance Spectroscopy (EIS). The electrochemical properties in terms of specific capacity, redox potentials vs Li+/Li, first cycle capacity loss, coulombic and energy efficiencies of these materials were investigated in coin-cell by Galvanostatic Cycling (GC). Finally, to elucidate the reaction mechanisms of the electrochemical processes involved in these materials, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) at room temperature were coupled and performed on the as-prepared glasses and on ex-situ (after cycling) materials at different electrochemical states of charge. This new study will bring significant elements to optimize both the glass composition and its elaboration conditions to obtain high performance cathode materials without critical materials.