How does nickel (Ni) modify two-dimensional black phosphorus to enhance its electrochemical lithium storage performance?

Recently, two-dimensional black phosphorus has shown very high potential for electrochemical lithium storage by virtue of its excellent properties. However, the defects of low electronic conductivity of two-dimensional black phosphorus itself and the tendency of volume expansion during charging and discharging also limit its development in the field of energy storage. In order to achieve better lithium storage performance, two-dimensional black phosphorus modified with Ni element was prepared by solvothermal synthesis in this study, and the high electron mobility of Ni element was used to modify the material. The synthesized material retained the morphology and properties of two-dimensional black phosphorus and its lithium storage performance were enhanced with excellent long cycling and rate performance. It had a first charge/discharge specific capacity of 651.58 mAh g−1 and 963.72 mAh g−1 at a current density of 0.1 A g−1, after which we constructed an approximate model of the material by calculation. The results of the band gap indicated that the conductivity of the material is enhanced, and the results of the lattice constant indicate that the problem of volume expansion of the system is improved. This study lays the foundation for future theoretical and practical applications of two-dimensional black phosphorus.