Large-Scale Synthesis of Electrochemically Active Titanium Diboride-Based Nanosheets by High-Energy Ball Milling

AlB2-type layered metal diborides have soughtrenewedresearch attention in recent years on account of their ability toyield XBenes their quasi-two-dimensional (2D)counterparts. These quasi-2D nanostructures present exciting avenuesto utilize the rich science offered by metal diborides. While a rangeof approaches have been developed to exfoliate layered metal diborides,the ability to obtain XBenes in a scalable manneris in its incipient stages this is a critical bottleneck intranslating their rich nanoscience into tangible technology. In thiswork, we present a scalable approach that employs high-energy ballmilling to exfoliate titanium diboride (TiB2) into itsquasi-2D counterparts at the gram scale. We first show that millingTiB(2) crystals for an optimal duration (6 h) and at a specificballs-to-powder ratio (20:1) yields multi-layer-thick nanosheets (& SIM;5-10nm thick). Second, by using Rietveld refinement and Raman spectroscopy,we show that the chemical integrity of TiB2 is retainedto a large extent upon exfoliation there is an associated formationof defects within the crystal structure of TiB2 that evolvewith milling. Finally, we show that upon milling, the native electrochemicalactivity of TiB2 is enhanced by several folds. This abilityto obtain nanosheets of TiB2 in a scalable manner usinga high-energy ball mill bridges a critical missing link in the fast-growingscience on nanoscaling AlB2-type metal borides.

Automated summary

In recent years, there has been renewed research interest in AlB2-type layered metal diborides due to their ability to yield XBenes. In this work, a scalable approach using high-energy ball milling is presented to exfoliate titanium diboride (TiB2) into multi-layer-thick nanosheets. The exfoliated TiB2 nanosheets retain their chemical integrity to a large extent and exhibit enhanced electrochemical activity.