Access to advanced sodium-ion batteries by presodiation: Principles and applications

Sodium-ion batteries (SIBs) are expected to offer affordability and high energy density for large-scale energy storage system. However, the commercial application of SIBs is hurdled by low initial coulombic efficiency (ICE), continuous Na loss during long-term operation, and low sodium-content of cathode materials. In this scenario, presodiation strategy by introducing an external sodium reservoir has been rationally proposed, which could supplement additional sodium ions into the system and thereby markedly improve both the cycling performance and energy density of SIBs. In this review, the significance of presodiation is initially introduced, followed by comprehensive interpretation on technological properties, underlying principles, and associated approaches, as well as our perspectives on present inferiorities and future research directions. Overall, this contribution outlines a distinct pathway towards the presodiation methodology, of significance but still in its nascent phase, which may inspire the targeted guidelines to explore new chemistry in this field.