Two-phase transition induced cation-disordered Li-reactive bi-metallic phosphides enabling high-performance Li-storage

Abstract

To resolve sluggish reaction kinetics of the single-component Ge anodes for Li-ion batteries, herein, we integrate GaP and Ge to construct a novel cation-disordered GaGeP2 compound via a simple mechanical ball milling method, which showcases significantly better Li-storage properties compared with GaP and Ge. The enhanced Li-storage performances can be attributed to the disordered lattice, which leads to faster Li-ionic and electronic reaction kinetics, and stronger anti-volume pulverization capability as confirmed by theoretical calculations and experimental validations. The cation-disordered GaGeP2 presents a highly reversible capacity of 1,410 mA h g−1 at 100 mA g−1 featuring an appropriate operating potential of 0.46 V and the initial Coulombic efficiency (ICE) up to 90% underpinned self-healing Li-storage mechanisms of intercalation reaction and followed by conversion reactions as characterized by in(ex)-situ XRD and ex-situ Raman and XPS. The GaGeP2@C composite delivers a robust cycling stability of remaining 651 mA h g−1 after 1200 cycles at 2000 mA g−1 and a high-rate capability of maintaining 525 mA h g−1 at 20,000 mA g−1. Broadly, such kind of two-phase transition induced cation-disordered Li-reactive bi-metallic phosphides with novel physicochemical properties will receive high attention from the energy storage field.