Carbon nanofiber bridged two-dimensional titanium carbide as a superior anode for lithium-ion batteries

Abstract

MXenes, a novel family of two-dimensional metal carbides, are receiving intense attention for lithium-ion batteries (LIBs) and supercapacitors because they have high volumetric capacitance exceeding all carbon materials. However, serious interlayer stacking exists in MXene particles, which greatly decreases the electrical conductivity in the bulk and hinders the accessibility of interlayers to electrolyte ions. Thus, multi-stacked MXene particles exhibit low capacitance and poor rate capability. Herein, we report an effective strategy to directly improve the electrochemical performance of multi-stacked MXene (Ti₃C₂T_x) particles as LIB anode materials. It was successfully realized by growing conductive “carbon nanofiber (CNF) bridges” within the gaps of each Ti₃C₂T_x particle as well as the outside. With the help of these CNFs, the as-prepared Ti₃C₂/CNF particles exhibited significantly improved reversible capacity compared with pure Ti₃C₂T_x particles. More remarkably, even at an ultrahigh rate of 100 C, the capacity of Ti₃C₂/CNF hybrid particles was just slightly lower than that of pure Ti₃C₂T_x particles at 1 C, and there was no capacity decay after 2900 cycles at 100 C, demonstrating excellent rate capability and superior long-term stability at the ultrahigh rate.