Mott-Schottky Effect in Core-Shell W@Wx C Heterostructure: Boosting Both Electronic/Ionic Kinetics for Lithium Storage.

Abstract

The dynamics rate of traditional metal carbides (TMCs) is relatively slow, severely limiting its fast-charging capacity for lithium-ion batteries (LIBs). Herein, the core-shell W@Wx C heterostructure is developed to form Mott-Schottky heterostructure, thereby simultaneously accelerating the electronic and ionic transport kinetics during the charging/discharging process. The W nanoparticles are partially reduced into Wx C to form a particular core-shell structure with abundant heterogeneous interfaces. Benefiting from the Mott-Schottky effect, the electrons at the metal/semiconductor heterointerface can migrate spontaneously to realize an equal work function on both sides. In addition, the independent nanoparticle as well as the unique core-shell structure facilitate the ionic diffusion kinetics. As expected, the W@Wx C electrode exhibits excellent electrochemical stability for LIBs, whose capacity can be maintained at 173.8mA h g-1 after 1600 cycles at a high current density of 5 A g-1 . When assembled into a full cell, it can achieve an energy density of 360.2Wh kg-1 . This work presents a new avenue to promote the electronic and ionic kinetics for LIBs anodes by constructing the unique Mott-Schottky heterostructure.