Scalable, Non-Toxic, Chemical Presodiation for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) present a promising alternative to lithium-ion batteries. However, many earth-abundant sodium-ion cathodes, such as P2-type layered oxides, are often sodium-deficient. As a result, pairing them with hard carbon anodes does not allow them to reach their full capacity. This work introduces a scalable, non-toxic chemical presodiation technique for both SIB cathodes and anodes, utilizing a novel sodium source. The novelty lies in the ability to systematically tune the sodium chemical potential of the sodium source, enabling the chemical sodiation of cathodes without overdischarging. Simultaneously, for the anode, the degree of charge can be adjusted by modifying the chemistry. This method promotes stable SEI formation, enhancing the initial Coulombic efficiency and cycling stability of hard carbon anode sodium-ion full cells.