Direct production of lithium nitrate from the primary lithium salt by electrodialysis metathesis

Abstract

As one of the most successful cathode materials, LiNi1-y-zMnyCozO2 (NMC) has become the preferred choice for automotive lithium-ion batteries (LIBs). Currently, its lithium source, LiOH, is not based on primary lithium salts and the route is unsustainable due to the large resource losses and high carbon footprint. In this study, a desirable alternative LiNO3 is synthesized directly from the primary lithium product LiCl and abundant NaNO3 by electrodialysis metathesis (EDM). Detailed online parameters (current/voltage/conductivity/pH/temperature) are recorded and product properties (volume/density/composition/purity) are also analyzed comprehensively. The effect of feed concentrations on the performance is intensively investigated as well. The results demonstrate that this one-step method with delicate ion metathesis can successfully prepare a highly pure (98.8%) and concentrated (118 g/L) LiNO3 solution. Meanwhile, the byproduct NaCl is virtually pure (>99%) and can also be used directly, so it is no burden to environment. Furthermore, a higher purity LiNO3 solid product (>99.7%) can be produced by integrating the evaporation process. The overall production cost has been carefully assessed and is as low as $0.219/kg. This work enables the volume production of LiNO3 in a green and cost-effective way, and broadens its application as a new precursor in the NMC synthesis, which can help to secure the supply chain of high-power LIBs.