Ni activated Mo2C by regulating the interfacial electronic structure for highly efficient lithium-ion storage

Abstract

Regulating the electronic structure plays a positive role in improving the ion/electron kinetics of electrode materials for lithium ion batteries (LIBs). Herein, an effective approach is demonstrated to achieve Ni/Mo₂C hybrid nanoparticles embedded in porous nitrogen-doped carbon nanofibers (Ni/Mo₂C/NC). Density functional theory calculations indicate that Ni can activate the interface of Ni/Mo₂C by regulating the electronic structure, and accordingly improve the electron/Li-ion diffusion kinetics. The charge at the interface transfers from Ni atoms to Mo atoms on the surface of Mo₂C, illustrating the formation of an interfacial electric field in Ni/Mo₂C. The formed interfacial electric field in Ni/Mo₂C can improve the intrinsic electronic conductivity, and reduce the Li adsorption energy and the Li⁺ diffusion barrier. Thus, the obtained Ni/Mo₂C/NC shows an excellent high-rate capability of 344.1 mA h g⁻¹ at 10 A g⁻¹, and also displays a superior cyclic performance (remaining at 412.7 mA h g⁻¹ after 1800 cycles at 2 A g⁻¹). This work demonstrates the important role of electronic structure regulation by assembling hybrid materials and provides new guidance for future work on designing novel electrode materials for LIBs.