Black Phosphorus Quantum Dots as Electrolyte Additives for Secondary Batteries

Abstract

The improvement of the electrochemical performance of a rechargeable battery can be achieve by the most common and efficient technique which is adding a functional additive to the battery electrolyte, which are mostly small organic molecules, although some work has used Quantum Dots as well. In this work, black phosphorous quantum dots (BPQDs) are used as an additive to enhance the battery performance having hard carbon as an anode material. Black phosphorus is a two-dimensional layered material with unique electronic and optoelectronic properties that make it an excellent candidate to explore in energy storage applications. The liquid-phase exfoliation method is used to obtain BPQDs using N-Methyl-2-Pyrrolidone (NMP) as a solvent. These BPQDs were incorporated in the hard carbon electrode my infiltration method. Half-cell were made to study the properties of BPQDs as an electrolyte additive. C- rate capabilities and cycling study were done along with some characterization techniques. The addition BPQDs is shown to increase the specific capacity (4%) at 200 mA/g; the increment is seen to be significantly higher (18%) at higher C rate that is at 500 mA/g. The BPQDs appear to be good electrolyte additive and shows some remarkable properties such as facilitate the Na surface diffusion, stress management by stabilizing the SEI, enhance the Na wetting and the specific discharged capacity of Na ion battery