From phosphorus nanorods/C to yolk–shell P@hollow C for potassium-ion batteries: high capacity with stable cycling performance

A thin hollow C (HC) was synthesized to host a high phosphorus (P) loading of 75 wt%, forming a P@HC yolk/shell structure, which delivered a reversible capacity of 841 mA h g⁻¹, with excellent rate capability and stable cycling performance. P vapor concentration was found to be critical to the formation of P@HC or the P nanorod (PNR)/C composite. At a very high concentration of P vapor, well-crystallized PNRs were formed, which, however helped to identify the potassiation mechanism.