Application of Sodium-Rich Multifunctional Hard Carbon Synthesized via Multi-Alloy Grafting Strategy for Presodiation in High-Performance Sodium-Ion Batteries.

In sodium-ion pouch batteries based on hard carbon, an additional source of active sodium significantly enhances the battery's initial coulombic efficiency and compensates for the loss of active sodium ions during cycling. This study investigates the interaction between metallic sodium with carbon materials and develops a composite powder material of sodium-rich lithium-aluminum using a multi-alloy grafting strategy, to replenish the initial loss of active sodium in the hard carbon materials. To enhance the stability and utilization of this highly active sodium source, a novel slurry system based on polyethylene oxide (PEO) as a binder and dimethyl carbonate (DMC) as a solvent is introduced.