Atomic-scale surface modifications and novel electrode designs for high-performance sodium-ion batteries via atomic layer deposition

Renewable clean energies such as wind and solar power are limited by their intermittent operation nature and therefore their wide implementation urgently needs large-scale stationary electrical energy storage (EES) devices. State-of-the art lithium-ion batteries (LIBs) are dominant in portable electronics and their next generation technologies hold great promise for transportation. In this context, the restricted reserves of lithium on earth make LIBs luxurious for large-scale stationary EES. As an alternative, sodium ions share a similar chemistry as lithium ions. In particular, sodium is very abundant and cost effective. To this end, sodium-ion batteries (SIBs) are very promising in meeting the needs of large-scale EES devices. However, as LIBs still have many issues, SIBs also face many technical challenges in anodes, cathodes, electrolytes, and battery interfaces. To address these problems, a large variety of strategies has been investigated. In the past decade, atomic layer deposition (ALD) has first emerged as a new thrust for LIBs and recently in the past few years, ALD has also shown itself to be a very powerful technique in tackling technical issues in SIBs. Exclusively featuring its atomic-scale accuracy in material growth, unrivaled uniform and conformal deposition in any shaped substrates, crystallinity-tunability, and low temperature, ALD as a vapor-phase film deposition process remains to date the only route to tackle the interfacial issues by simply applying an ultrathin layer over battery electrodes. At the same time, ALD also distinguishes itself as an important avenue in searching for novel nanomaterials and solely enables optimizing materials in size, morphology, crystallinity, and composition. All these make ALD an irreplaceable tool in developing next-generation battery technologies. In this review, we summarize the updated advances of ALD in SIBs, covering atomic-scale surface modifications and novel electrode designs. The review is expected to stimulate more extensive and insightful studies on using ALD for high-performance SIBs.