Scalable manufacture of nearly pure-phase metallic MoS2 nanosheets
Ziwei Jeffrey Yang, Zhuangnan Li, Leyi Loh, James Moloney, J. Walmsley, Jiahang Li, Yuehua Chen, Lixin Liu, Han Zang, Han Yan, S. Sarkar, J. Kevin Day, Yan Wang, Manish Chhowalla
Abstract
Abstract Metallic, two-dimensional molybdenum disulfide (MoS 2 ) nanosheets show promise for energy storage and catalysis applications. However, current chemical exfoliation methods require more than 48 h 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 g h −1 ) production of nearly pure-phase metallic two-dimensional MoS 2 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 a 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 a high volumetric capacitance of 753.0 ± 3.6 F cm −3 and a specific capacity of 1,245 ± 16 mAh g −1 (electrolyte-to-sulfur ratio, 2 µl mg −1 ), respectively. Our method provides a practical pathway for producing high-quality metallic two-dimensional materials for high-performance energy devices.