Unlocking the Potential of Phosphorus Anodes for Sodium‐Ion Batteries via Tailored Reversible Na/Polyphosphide Chemistry

Abstract To surmount the inherent limitations and fully harness the remarkable ultra‐high specific capacity (2,596 mAh g −1 ) of phosphorus (P) anode for sodium‐ion batteries (SIBs), we unveil an alternative fast and reversible electrochemical pathway based on Na 2 P 16 ↔Na 3 P, which transcends the barriers posed by sluggish reaction kinetics in solid‐state red P. It entails the immobilization of dissolved sodium polyphosphide (Na 2 P 16 ) onto carbon cloth (CC) matrices via robust C─O─P bonding (Na 2 P 16 @CC), and the intrinsic superior malleability of Na 2 P 16 effectively mitigates the issue of electrode pulverization caused by volumetric changes of red P during (de)sodiation. Additionally, the profound chemical adsorption of surface oxygen‐doped CC toward phosphorus species and the utilization of weakly solvating cyclic carbonate solvents synergistically inhibit the vexing dissolution of high‐order polyphosphides in the electrolyte. By capitalizing on the advances of the novel reaction mechanism, the Na 2 P 16 @CC composite anode material achieves improved sodium storage performance with a high initial reversible capacity of 1.75 mAh cm −2 at 0.1 mA cm −2 and a capacity retention of 81% over 600 cycles. This work opens an avenue toward the rational design of P‐based anodes for high‐energy SIBs.