Metallic, two - dimensional (2D) molybdenum disulfide (MoS2) nanosheets show promise for energy storage and catalysis applications. However, current chemical exfoliation methods require more than 48 hours to produce milligrams of material, and result in an impure mixture of metallic (1T/1T’, approximately 50% – 70%) and semiconducting (2H) phases. Here, we demonstrate large-scale and rapid (> 600 grams per hour) production of nearly pure metallic phase 2D MoS2 nanosheets using microwave irradiation. Atomic resolution imaging and X-ray photoelectron spectroscopy show nearly 100% metallic phase in the basal plane. This high purity leads to large exchange current density (0.175 ± 0.030 mA cm-2) and low Tafel slopes (39 – 47 mV dec-1) for hydrogen evolution reaction. In supercapacitors and lithium-sulfur pouch cell batteries, the resulting nanosheets enable high volumetric capacitance of 753.0 ± 3.6 F cm-3 and specific capacity of 1245 ± 16 mAh g-1 (electrolyte-to-sulfur ratio = 2 μL mg-1), respectively. Our method provides a practical pathway for producing high quality metallic 2D materials for high performance energy devices.
Yang et al. (Fri,) studied this question.