Semi-metallic PC5 monolayer as a superior anode material for potassium ion batteries: A first principles study

Potassium ion batteries (PIBs) have been widely considered as appealing alternatives to lithium ion batteries (LIBs) because of their low-cost, good safety and high energy density; however, it is still challenging to search an outstanding anode material for PIBs owing to the big-size of potassium and sluggish reaction dynamics. Herein, using first principles computations, we identified an emerging phosphorous carbide (PC5) monolayer as a promising anode candidate of PIBs. The PC5 monolayer exhibits high electrical conductivity, which ensures rapid electronic transport during cycling. Moreover, the potassium diffusion barrier of PC5 is 0.18 eV, implying a high ionic mobility. On the whole intercalation process, the PC5 monolayer has strong affinity toward potassium and small volume expansion (0.57%), which could avoid the metallic dendrite formation and improve the cycle life. Remarkably, the specific capacity of PC5 is as high as 835.18 mA h/g, superior to many reported 2D materials. All the encouraging results reveal that PC5 is a high-performance anode of PIBs.

Automated summary

Through first principles computations, an emerging phosphorous carbide (PC5) monolayer was identified as a promising anode candidate for potassium ion batteries (PIBs). The PC5 monolayer exhibits high electrical conductivity, rapid electronic transport, and high ionic mobility. It has strong affinity toward potassium, small volume expansion, and high specific capacity, making it a high-performance anode material for PIBs.