Titanium diboride-based hierarchical nanosheets as anode material for Li-ion batteries

Abstract

Two-dimensional (2D) materials are enabling us to pursue several exciting avenues to enhance the performance of electrochemical energy-storage devices. Particularly, 2D nanostructures based on transition-metal diborides (TMDs) are theoretically predicted to possess an exceptionally high rate and long cycling stability for Li-ion storage owing to the intrinsic presence of boron honeycomb planes and multivalent transition-metal atoms. In this study, we present the first experimental investigation of the Li-ion storage potential of one such TMD-based nanostructure-titanium diboride (TiB2)-based hierarchical nanosheets (THNS). We demonstrate that THNS can be utilized as a high-rate anode material for Li-ion battery (LIB) and that a discharge capacity as high as ?380 mA h g-1 can be obtained at a current rate of 0.025 A g1- galvanostatic charge/discharge. Further, a discharge capacity of 174 mA h g-1 can be obtained at a current rate of 1 A g1- (charge time of ?10 min) with a capacity retention of 89.7% after 1000 cycles. We also demonstrate that the THNS-based LIB anode can sustain extremely high current rates (15 to 20 A g1-) allowing ultrafast charging in 9-14 s, and considerable discharge capacity (50 to 60 mA h g-1) with a capacity retention of over 80% after 10000 cycles. We also present some insights into the charge-storage characteristics of THNS-based anodes using ex situ electrochemical field emission scanning electron microscopy and X-ray photoemission spectroscopy measurements.