Realizing a 3C Fast-Charging Practical Sodium Pouch Cell.

Sodium-ion batteries (SIBs), endowed with relatively small Stokes radius and low desolvation energy for Na+, are reckoned as a promising candidate for fast-charging endeavors. However, the C-rate charging capability of practical energy-dense sodium-ion pouch cells is currently limited to ≤1C, due to the high propensity for detrimental metallic Na plating on the hard carbon (HC) anode at elevated rates. Here, an ampere-hour-level sodium-ion pouch cell capable of 3C charging is successfully developed via phosphorus (P)-sulfur (S) interphase chemistry. By rational electrolyte regulation, desired P-S constituents, namely, Na3PO4 and Na2SO4, are generated in the solid-electrolyte interphase with favorable Na+ interface kinetics. Specifically, Na+ desolvation energy barrier has been greatly lowered by the weak ion-solvent coordination near the inner Helmholtz plane on Na3PO4 interphase, while Na2SO4 expedites charge carrier mobility due to its intrinsically high ionic conductivity. Consequently, an energy-dense (126 Wh kg-1) O3-Na(Ni1/3Fe1/3Mn1/3)O2||HC pouch cell capable of 3C charging (100% state of charge) without Na plating can be achieved, with a great capacity retention of 91.5% over 200 cycles. Further, the assembled power-type Na3V2(PO4)3||HC pouch cell displays an impressive fast-charging capability of 50C, which surpasses that of previously reported high-power SIBs. This work serves as an enlightenment for developing fast-charging SIBs.