Synergetic enhancement of sodium storage in gallium-based heterostructures

Highlights: • The uniform Ga₂O₃@Ga₂S₃@C heterostructures are developed by a two-step method. • The Ga₂O₃@Ga₂S₃@C is an outstanding anode for sodium-ion batteries (SIBs). • High capacity, superior rate capability and cycle stability for SIBs are achieved. • Built-in electric field and interfacial effect in heterostructures help Na storage. Gallium chalcogenides, emerging as promising anode for sodium-ion batteries (SIBs), show high capacity utilization and self-healing ability but poor electrochemical performance owing to their inferior electrical conductivity and sluggish ion diffusion. Building heterostructures is regarded as a valid strategy to facilitate carrier transfer and boost sodium storage. Herein, we develop a controllable two-step approach to synthesize the Ga₂O₃@Ga₂S₃@C heterostructures. Serving as the anode for SIBs, it exhibits a reversible capacity of 680 mAh g⁻¹ at a current density of 0.1 A g⁻¹ after 100 cycles, as well as superior cyclic stability (410 mAh g⁻¹ at an ultrahigh current density of 20.0 A g⁻¹ over 4000 cycles). The mechanism for the enhanced sodium storage of Ga₂O₃@Ga₂S₃@C heterostructures is disclosed, which is mainly ascribed to the synergistic effect of built-in electric field and interfacial effect in p-n junctions, helping the sodium ions diffusion and the further conversion reactions.