Preparation and structure study of phosphorus-doped porous graphdiyne and its efficient lithium storage application

Heteroatomic doping (such as N, B, S, P) is one of the most effective strategies to improve the electrochemical performance of carbon-based materials. Herein, 2D phosphorus doped graphdiyne (P-GDY) is prepared via a facile calcination method with phosphoric acid as phosphorus source, and the structure-function relationship of P doping and the electrochemical performance of P-GDY are also investigated using a method combining experiment and density functional theory (DFT) calculations. X-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FTIR) verify that phosphorus (P) is doped in GDY framework via the forms of P-O, P = O and P-C bonds. Raman spectra and Brunauer-Emmett-Teller (BET) results reveal that the P doping creates numerous heteroatomic defects and active sites, causes more hierarchical micro-mesoporous, which provide more storage sites of Li and transmission paths for corresponding ions. Besides, DFT results imply that the most stable geometries can be obtained when the P-containing groups are doped at the benzene in GDY structure, and the doping P = O bonds are beneficial to Li storage. As a result, for P-GDY, enhanced electrochemical performances for lithium-ion batteries are obtained compared with pristine GDY, including higher reversible capacity, improved rate performance, and superior cycling stability.