Scaled-Up Synthesis of High-Energy Vanadyl Phosphate LIB Cathode Material

Lithium-ion batteries (LIBs) have rapidly become the focus of renewable energy storage over the past decade due to their high cycle life, energy density, and capacity. With the automobile industry preparing for a significant increase in electric vehicle (EV) production, it is more important than ever to develop high-energy cathode materials. These materials should ideally be cobalt and nickel-free. Vanadium is the fourth most abundant transition metal, and moreover can undergo a two redox reaction, from V 5+ to V 3+ . Vanadyl phosphate (VOPO 4 ) has shown increasing promise as a viable cathode material for lithium-ion batteries as it is capable of intercalating up to 2 Li + ions reversibly, reaching a capacity that exceeds 300 mAh/g and an energy density higher than commercial NMC cathodes. However, an underlying issue surrounding this material is that it is not commercially available so must be made in-house. ε- VOPO 4 with excellent electrochemical performance, reported by our team, was synthesized via a solvothermal method which normally gives a low (~1.5 g) product yield for one batch synthesis. The primary focus of this work is to increase the yield without sacrificing the electrochemical performance. By increasing the concentration of reagents while keeping the amount of solvent<br/>constant, VOPO 4 synthesis has been successfully scaled up by a factor of five. Although some particle morphology changes occurred with increased reagent concentration, possibly due to pressure changes inside the reaction vessel, there is no discernible influence on electrochemical performance. By monitoring the physical properties of each synthesis, an optimal procedure will be developed to scale up the production of VOPO 4 to 100 g per batch. This work was supported by the NorthEast Center for Chemical Energy Storage (NECCES).