Sodium storage mechanism of a GeP5/C composite as a high capacity anode material for sodium-ion batteries.

The sodium storage mechanism of a GeP₅/C composite electrode was revealed. Metallic Ge formed during discharge enhances the electronic conductivity of the electrode, while Na_xP mitigates the agglomeration and volume change of Ge in the alloying process. The GeP₅ phase is regenerated after recharge along with elemental Ge and P, implying a reversible phase transition of GeP₅ during cycling. [ABSTRACT FROM AUTHOR]