The same changes of the S species were observed in the 2 nd cycle (Figure ) but with stronger S 0 peak intensity. This suggests during depotassiation, S species was oxidized alongside the partial oxidation of metallic Mo, leading to the formation of S 0 after charge, which essentially contributes to electron transfer and thus capacity. To ascertain our results, we tested the Raman spectra of the MoS2 electrodes at charged states (depotassiation) in the 1 st and 2 nd cycles. As shown in Figure , compared to pristine MoS2, the signature E 1 2g and A1g vibrational modes largely diminished, signaling the partial restoration of pristine MoS2. New peaks evolved at 155 and 244 cm -1 in both cycles, corresponding to the torsion and bending vibration modes of sulfur (S8) and therefore further proving the formation of S 0 after depotassiation. Our analysis of the S species in MoS2 points to the fact that, beside Mo, S was electrochemically active after the first potassiation and participated in the oxidation and reduction reactions in the following cycles, effectively making K-S chemistry a part of the K storage mechanism in MoS2; in another word, the mechanism is based on both Mo cationic redox and S anionic redox activities. As known, the S conversion process involved in K-S chemistry can lead to the formation of both low-order polysulfides and high-order polysulfides, the latter of which are in the liquid form and can dissolve in electrolytes. If K-S chemistry were to take part in the K storage in MoS2, we would see high-order polysulfides formed during potassiation dissolving in the electrolyte; as expected, we detected the absorption peaks of S6 2-and S5 2-at 300 and 318 nm, respectively, in the UV-vis absorption spectrum of the electrolyte extracted from the separator after the 2 nd discharge (Figure ). In the case of Route A, since the discharge depth was kept at 0.001 V in all cycles, it is expected that Mo cationic redox and