Phosphorus-rich tin phosphide-carbon nanotubes composite as a high-performance anode for potassium ion batteries

Tin phosphides, especially phosphorous-rich tin phosphides, have recently attracted increasing attention as promising anode materials for potassium ion batteries (PIBs) because of their high theoretical capacities and suitable operating voltages. However, large volume changes during potassiation/depotassiation processes severely limit their performances. Herein, SnP3/carbon nanotubes (SnP3/CNTs) composite was successfully prepared through a ball-milling technique and investigated as a novel anode material for PIBs. The SnP3/CNTs20 composite electrode delivered a reversible capacity of 373 mAh g(-1) at 200 mA g(-1) after 100 cycles and exhibited excellent rate capabilities. After 150 cycles at 1000 mA g(-1), a high capacity of 190 mAh g(-1) remained. The superior performances of SnP3/CNTs-20 composite electrode were ascribed to the critical roles of CNTs matrix in buffering volume expansion, boosting electrical conductivity, and avoiding over thick SEI film. Furthermore, the phase transformation and structural evolution of the SnP3/CNTs-20 composite were identified by exploiting ex-situ X-ray diffraction (XRD) and ex-situ scanning electron microscope (SEM), respectively. These results are expected to inspire the development of advanced tin phosphide based anode materials for PIBs.

Automated summary

A SnP3/CNTs composite electrode was successfully prepared through ball-milling technique and demonstrated excellent cyclic performance and rate capabilities for PIBs. The critical roles of CNTs matrix in buffering volume expansion, boosting electrical conductivity, and avoiding over thick SEI film were identified for the superior performances of the composite electrode. The results are expected to inspire the development of advanced tin phosphide based anode materials for PIBs.