Ni activated Mo 2 C by regulating the interfacial electronic structure for highly efficient lithium-ion storage.

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/Mo 2 C hybrid nanoparticles embedded in porous nitrogen-doped carbon nanofibers (Ni/Mo 2 C/NC). Density functional theory calculations indicate that Ni can activate the interface of Ni/Mo 2 C 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 Mo 2 C, illustrating the formation of an interfacial electric field in Ni/Mo 2 C. The formed interfacial electric field in Ni/Mo 2 C can improve the intrinsic electronic conductivity, and reduce the Li adsorption energy and the Li + diffusion barrier. Thus, the obtained Ni/Mo 2 C/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.