Our work on lithium and sodium ion exchange in layered oxides appears in Nature Materials

Our collaborative paper “Uncovering the Predictive Pathways of Lithium and Sodium Interchange in Layered Oxides” is out in Nature Materials, with Weihang Xie from our group among its authors.

Ion exchange, swapping the sodium in a material for lithium or the other way round, is a powerful way to make metastable electrode materials that cannot be synthesized directly, but it usually needs a large excess of lithium, and its reaction pathways were unclear. Using layered oxides as model materials, the study shows that the number of vacancies, and the preference for lithium that comes with it, decides which exchange pathways are open. With this understanding, the team made Na_yCoO₂ from Li_xCoO₂, and Li_0.94CoO₂ back from Na_yCoO₂, in solutions with as little as one lithium for every 1,000 sodium ions, by an electrochemically assisted exchange. The results open new routes to the predictive synthesis of electrode materials and to the separation of lithium from sodium.