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

Abstract

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.