Triggering the Phase Conversion of GeP from Monoclinic to Cubic by Zn Substitution toward a High‐Rate Ge1−xZnxP Solid Solution Anode for Li‐Ion Batteries

Abstract The monoclinic GeP with large capacity, low plateau, and high initial coulombic efficiency (ICE) has been proved to be alternative anode for Li‐ion batteries. However, the heavy use of Ge raw material with its high price, hinders its further development. Herein, the Zn atom is proposed for substitution into GeP and replaces part of the Ge owing to its low price, suitable plateau, and similar radius. Interestingly, a novel Ge 1−x Zn x P solid solution with a wide range tunable region (0.143 < x < 0.6) is achieved, reducing the heavy use of Ge and cutting the GeP price down. More intriguingly, such Ge 1−x Zn x P possesses a new phase, different from monoclinic GeP, which is first verified to be a cubic system in F‐43m. Compared to semi‐conducting GeP, this cubic Ge 1−x Zn x P phase possesses metallic conductivity, thus enabling a better rate performance than monoclinic GeP (e.g., 881 vs 283 mAh g −1 at 2000 mA g −1 ), while keeping the great advantages of large capacity, low plateau, and high ICE of GeP as well. Consequently, the assembled LiCoO 2 //Ge 1−x Zn x P full cell exhibits large capacity over 1000 mAh g −1 . This unique phase control strategy by atomic substitution can be easily extended to manipulate electrochemical behaviors of other multi‐phase materials toward advanced energy storage.