WS-Graphite Dual-Ion Batteries.

A novel WS-graphite dual-ion battery (DIB) is developed by combining a conventional graphite cathode and a high-capacity few-layer WS-flake anode. The WS 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 at concentration of 10 g L and exfoliation yield of 100%) of few-layer WS flakes in dispersion. The WS anodes enable DIBs, based on hexafluorophosphate (PF) and lithium (Li) ions, to achieve charge-specific capacities of 457, 438, 421, 403, 295, and 169 mAh g at current rates of 0.1, 0.2, 0.3, 0.4, 0.8, and 1.0 A g, respectively, outperforming conventional DIBs. The WS-based DIBs operate in the 0 to 4 V cell voltage range, thus extending the operating voltage window of conventional WS-based Li-ion batteries (LIBs). These results demonstrate a new route toward the exploitation of WS, and possibly other transition-metal dichalcogenides, for the development of next-generation energy-storage devices.