Alternatives to Cobalt: Vanadate Glass and Glass-Ceramic Structures as Cathode Materials for Rechargeable Lithium-Ion Batteries

Abstract

Cobalt-based layered materials have been dominant as cathodes for the rechargeable lithium-ion battery since it was introduced in 1991. Recently, the focus has been on finding novel cathode materials that have significantly higher capacity or voltage than lithium cobalt oxide (practical specific capacity ∼ 140 mA h/g and average voltage ∼ 3.8 V). However, because of the cost and sourcing issues involved with cobalt, which predominately comes from the Democratic Republic of the Congo, looking for less expensive and more abundant alternatives with comparable performance is a growing focus. Here, we report that glass and glass-ceramic vanadate materials showed high initial capacity (>300 mA h/g) and promising cycling stability. Vanadate glass and glass ceramics also showed good rate performance and deeper discharge capability (down to 1.5 V) compared to crystalline counterparts reported in literature. X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy (EDS), and Raman spectroscopy were used to explore the processing-structure–property relationship of vanadate glass and glass-ceramics as novel electrodes. The results indicate that the glass-ceramic-containing β-Li₀.₃₃V₂O₅ crystal has higher initial capacity, but the amorphous glass vanadate shows the most stable cycling performance. Despite the promising performance of glass-based electrodes in which structural stability is not an issue, the continued degradation was still observed. Raman and EDS analyses suggest that vanadate-based cells have the dissolution of vanadium in electrolyte that transports to the lithium metal anode, which is a key issue that must be overcome for these materials to be more stable and commercially applicable.