Prediction of a flexible anode material for Li/Na ion batteries: Phosphorous carbide monolayer (α-PC)

Abstract High performance anode materials are crucial for the design and fabrication of alkali ion batteries. Here, using first-principles calculations, we demonstrate that the recently-synthesized phosphorous carbide monolayer (α-PC) is identified as an ideal flexible anode material for Li/Na ion batteries. Compared with other well documented anodes including graphene and phosphorene, α-PC has the advantages of strong adsorption affinity and fast diffusion channels for Li and Na ions. The theoretical storage capacity reaches 623.2 mAh g-1 for Li and 467.4 mAh g-1 for Na with a suitable open circuit voltage range. More importantly, α-PC is rather flexible along the direction crossing the grooves with elastic constant of only 13.1 GPa nm. Benefitted from the puckered structure, α-PC demonstrates a stable structure and suitable binding/diffusion energetics to Li/Na ions under a wide range of strain up to 21%. These unique features make α-PC an ideal anode material for the design and fabrication of future flexible batteries.