WS₂–Graphite Dual-Ion Batteries

Abstract

A novel WS₂-graphite dual-ion battery (DIB) is developed by combining a conventional graphite cathode and a high-capacity few-layer WS₂-flake anode. The WS₂ flakes are produced by exploiting wet-jet milling (WJM) exfoliation, which allows large-scale and free-material loss production (i.e., volume up to 8 L h^-1 at concentration of 10 g L^-1 and exfoliation yield of 100%) of few-layer WS₂ flakes in dispersion. The WS₂ anodes enable DIBs, based on hexafluorophosphate (PF₆^-) and lithium (Li⁺) ions, to achieve charge-specific capacities of 457, 438, 421, 403, 295, and 169 mAh g^-1 at current rates of 0.1, 0.2, 0.3, 0.4, 0.8, and 1.0 A g^-1, respectively, outperforming conventional DIBs. The WS₂-based DIBs operate in the 0 to 4 V cell voltage range, thus extending the operating voltage window of conventional WS₂-based Li-ion batteries (LIBs). These results demonstrate a new route toward the exploitation of WS₂, and possibly other transition-metal dichalcogenides, for the development of next-generation energy-storage devices.