Sn₄P₃ nanoparticles confined in multilayer graphene sheets as a high-performance anode material for potassium-ion batteries

Phosphorus-based anodes are highly promising for potassium-ion batteries (PIBs) because of their large theoretical capacities. Nevertheless, the inferior potassium storage properties caused by the poor electronic conductivity, easy self-aggregation, and huge volumetric changes upon cycling process restrain their practical applications. Now we impregnate Sn₄P₃ nanoparticles within multilayer graphene sheets (Sn₄P₃/MGS) as the anode material for PIBs, greatly improving its potassium storage performance. Specifically, the graphene sheets can efficiently suppress the aggregation of Sn₄P₃ nanoparticles, enhance the electronic conductivity, and sustain the structural integrity. In addition, plenty of Sn₄P₃ nanoparticles impregnated in MGS offer a large accessible area for the electrolyte, which decreases the diffusion distance for K⁺ and electrons upon K⁺ insertion/extraction, resulting in an improved rate capability. Consequently, the optimized Sn₄P₃/MGS containing 80 wt% Sn₄P₃ (Sn₄P₃/MGS-80) exhibits a high reversible capacity of 378.2 and 260.2 mAh g⁻¹ at 0.1 and 1 A g⁻¹, respectively, and still delivers a large capacity retention of 76.6% after the 1000th cycle at 0.5 A g⁻¹.