K0.36(H2O)yWS2: a new layered compound for reversible hydrated potassium ion intercalation in aqueous electrolyte

This work reports the synthesis of a new quasi two-dimensional layered compound, K0.36(H2O)yWS2, for aqueous potassium ion storage. Its crystal structure determined by single crystal X-ray diffraction is composed of WS2 layers and disordered hydrated K+ stacking along the c direction alternately. Due to the large interlayer spacing and high conductivity, K0.36(H2O)yWS2 is demonstrated to be a stable host for reversible intercalation and de-intercalation of hydrated K+ in K2SO4 aqueous solution.