Pre-intercalation: A valuable approach for the improvement of post-lithium battery materials

With the growing concern around the sustainability and supply of lithium, the need for alternative rechargeable energy storage technologies has become ever more pressing. Sodium-, potassium-, magnesium-, and zinc-ion batteries are fast becoming viable alternatives but are held back by capacity, rate and stability problems that have not developed comparably to lithium-ion batteries. To overcome these shortcomings and reduce the reliance on lithium, electrode materials used for these post-lithium batteries must be improved. Pre-intercalation of foreign species into the lattice of promising electrode materials can enhance their electrochemical performance in comparison to the un-pre-intercalated counterparts, closing the performance gap with lithium-ion batteries. This review article covers the common methods of pre-intercalating foreign species into electrode materials, the resulting structural effects and the improvements that are observed in the materials' electrochemical performance for post-lithium batteries. Timely and impactful work reported previously are summarised as examples of these improvements, demonstrating the value and ever-growing importance of pre-intercalation in today's battery landscape.