Disordered GaSiP solid solution anodes with liquid metal phase for high-performance Li-ion batteries

Abstract

Silicon (Si) has become the most promising next-generation anode to replace commercial graphite for Li-ion batteries (LIBs) profiting from its large reversible capacity of 4,200 mA h g⁻¹. However, its sluggish reaction kinetics and large volume effect need to be resolved. Herein, we prepare a ternary GaSiP solid solution with a disordered lattice by a facile mechanochemistry method. As anodes of LIBs, the GaSiP provides a reversible capacity of 1,527 mA h g⁻¹ at 100 mA g⁻¹ with an initial Coulombic efficiency (ICE) of 90.8% based on the reversible Li-storage mechanism integrated intercalation and subsequent conversion processes as confirmed by crystallography characterization and electrochemical measurements. Importantly, the GaSiP carbon composite presents a long cycling stability of maintaining 1,362 mA h g⁻¹ after 50 cycles at 0.1 A g⁻¹, and 75% capacity retention rate after 1,200 cycles at 2 A g⁻¹, and a high-rate performance of remaining 440 mA h g⁻¹ at 20 A g⁻¹. Broadly, this work opens the door to develop ternary phosphides with disordered lattice and liquid metallic phase using for electrochemical energy conversion and storage.