Recently, the iChEM researcher, Prof. Yi Xie’s group in University of Science and Technology of China made new progress in the design of the high conductive two-dimensional materials. The result was published in Angew. Chem. Int. Ed. (doi:10.1002/anie.201600029), entitled “Superior Electrical Conductivity in Hydrogenated Layered Ternary Chalcogenide Nanosheets for Flexible All-Solid-State Supercapacitors”.

Ultrathin two-dimensional crystals with unique electronic structure characteristics are considered as the best materials to build the next-generation nanoelectronics. However, most of the two-dimensional materials show low electrical conductivity, which hampers their practical applications. As the conductive properties of ultrathin 2D crystals are strongly related to the electronic structure, researchers show that the conductive nature of layered ternary chalcogenide with formula of Cu₂WS₄ (M = Mo, W; X = S, Se) can be switched from semiconducting to metallic by hydrogen incorporation.

By taking Cu₂WS₄ as example, the hydrogenated-Cu₂WS₄ nanosheets are obtained by a lithium intercalation assisted exfoliation strategy. The experimental results provide direct evidence for a semiconductor-to-metal transition between pristine Cu₂WS₄ and hydrogenated-Cu₂WS₄ nanosheets. Meanwhile, the room-temperature electrical conductivity of hydrogenated-Cu₂WS₄ nanosheet film was almost 10¹⁰ times higher than that of pristine bulk sample with a value of about 2.9×104 S m−1. In addition, hydrogenated-Cu₂WS₄ nanosheet is with robust metallicity, which can be kept even after temperature treatment at 350 °C. With the high conductivity and stable metallicity of hydrogenated-Cu₂WS₄ nanosheet, the fabricated all-solid-state flexible supercapacitor based on it shows promising electrochemical performances. This work also paves the new way in searching for highly conductive electrodes.

paper link：http://onlinelibrary.wiley.com/wol1/doi/10.1002/anie.201600029/full