Unusual Li-Storage Behaviour of Two-Dimensional ReS₂ Single Crystals

Unusual Li-storage properties are observed for two-dimensional ReS₂ compared to its analogue MoS₂. First, we prepared ReS₂ single crystals (99.9 % crystallinity) by chemical vapour transport with high yield and utmost purity. Li-storage properties are assessed using a standard half-cell assembly with metallic Li as the counter electrode. The highly crystalline ReS₂ rendered excellent electrochemical characteristics with interesting features. This logically leads to further exploration of ReS₂ towards Li-storage. Indeed, ReS₂ could act as efficient intercalation host for Li-ions with lower redox potential (∼1.2 V vs. Li) and decent reversibility (∼0.4 mol Li). On the other hand, high reversibility is registered while deep discharging of the active material. This eventually obeys the perfect conversion pathway. Interestingly, electrochemically activated ReS₂ also rendered good reversibility and eventually serves as an insertion host with a working potential of ∼2 V vs. Li.