Exfoliation of Few-Layer Black Phosphorus in Low-Boiling-Point Solvents and Its Application in Li-Ion Batteries

Abstract

The liquid-phase exfoliation (LPE) of black phosphorus (BP) is a strategic route for the large-scale production of phosphorene and few-layer BP (FL-BP) flakes. The exploitation of this exfoliated material in cutting-edge technologies, e.g., in flexible electronics and energy storage, is however limited by the fact that the LPE of BP is usually carried out at a high boiling point and in toxic solvents. In fact, the solvent residual is detrimental to device performance in real applications; thus, complete solvent removal is critical. Here, we tackle these issues by exfoliating BP in different lowboiling-point solvents. Among these solvents, we find that acetone also provides a high concentration of exfoliated BP, leading to the production of FL-BP flakes with an average lateral size and thickness of ∼30 and ∼7 nm, respectively. The use of acetone to produce less defective few-layer BP flakes (FL-BP acetone ) from bulk crystals is a straightforward process which enables the rapid preparation of homogeneous thin films thanks to the fast solvent evaporation. The ratio of edge to bulk atoms for the BP flakes here produced, combined with the use of low-boiling-point solvents for the exfoliation process, suggests that these thin films are promising anodes for lithium-ion batteries. To this end, we tested Li-ion half cells with FL-BP acetone anodes achieving a reversible specific capacity of 480 mA h g −1 at a current density of 100 mA g −1 , over 100 charge/discharge cycles. Moreover, a reversible specific capacity of 345 mA h g −1 is achieved for the FL-BP acetone -based anode at high current density (i.e., 1 A g −1 ). These findings indicate that the FL-BP acetone -based battery is promising with regards to the design of fast charge/ discharge devices. Overall, the presented process is a step forward toward the fabrication of phosphorene-based devices.

Black Phosphorus, a Rising Star 2D Nanomaterial in the Post‐Graphene Era: Synthesis, Properties, Modifications, and Photocatalysis Applications

“…Owing to the outstanding physical and chemical property of BP as a rising star, BP has been applied in many fields such as batteries anodes, selective sensors, and field‐effect transistors, and these applications have been reviewed by many articles . Apart from aforesaid applications, BP, as a promising photocatalyst, has been applied in the field of photocatalysis for solar‐to‐energy conversion, photocatalytic carbon dioxide reduction, photocatalytic hydrogenation, environmental pollutants treatment, solar‐driven nitrogen fixation and antibacterial application, and cancer treatments.…”

“…In the past few years, there are many articles that have reported the practical application of BP in batteries, photodetectors, sensors, field‐effect transistors, and solar cells, and these applications have been summarized in some reviews . Meanwhile, many papers have reported the application of photocatalysis field, while there is no article that has detailedly reported that BP as a photocatalyst is employed in various aspects.…”

Chemical and Electrochemical Lithiation of van der Waals Tetrel‐Arsenides

“…Many layered materials such as graphite,M oS 2 ,S n 4 P 3 ,a nd black Pa re being studied for their electrochemical applications in lithium-ionb atteries. [1,2,[12][13][14][15][16][27][28][29][30][31][32][33][34] Theoryh as predicted that tetrel-based layered graphitea nalogs, silicene, germanene, and stanene may be suitable for battery applications. [35,36] In addition, lithiated tetrels with layered structures have been studied to better understandt he reactionp rocesses occurring in Ge and Si anodes.…”

Tuning the Optical and Electrical Properties of Few‐Layer Black Phosphorus via Physisorption of Small Solvent Molecules

“…An indirect way to gain insight into the affinity of the solvent molecules for the BP consists in the ability of the given solvent to disperse the 2D material, e.g., in the case of liquid phase exfoliation. Previous work revealed that BP is poorly dispersed in solvents with lower surface tension such as acetone, IPA and ethanol, which implies an unfavorable adhesion of these solvent molecules onto the surface of BP . In other words, the number of molecules physisorbed in a given surface area of BP for these three solvents is smaller when compared to aromatic solvents.…”