First-principle study of highly controllable boron-doped graphene (BC20) as a high-capacity anode for potassium-ion batteries

Abstract

Abstract Designing new anode materials with high performance is vital for the development of full-cell potassium-ion batteries (KIBs). Although boron-doped graphene (BDG) anodes have been widely studied for lithium- and sodium-ion batteries, there are few works considering BDG anodes with controllable doping concentration applied for KIBS. Herein, by first-principle calculations, we propose a novel BDG with controllable doping concentration as a promising anode material for KIBs. As a result, the chemisorption ability of the proposed BDG (BC20) for K is greatly enhanced in comparison with the pristine graphene, since the B dopants introduce electron-deficiency. Besides, the diffusion energy barrier of K on the surface of BC20 is as low as 0.19 eV, indicating high-rate performance. Noticeably, the maximum K storage capacity is 854 mAh g−1 with a low open circuit voltage (OCV) of 0.29 V. Moreover, the chemical window of OCV is in a low range without large variation, which is favorable for providing a large operating voltage. The results suggest that the presented BC20 is not only a promising anode candidate for KIBs; but also opens an avenue for designing novel BDG structures with controllable doping concentration applied to energy storage.