It is well-known that in neutral and acidic aqueous electrolytes, MoS2 monolayers can store charges by adsorption of cations on to the electrode-electrolyte interface as its analog of graphene. Restricted by its low conductivity and the charge storage mechanism, the electrochemical performance of MoS2 monolayer supercapacitor electrode is not satisfactory. It is reported here that water bilayers absorbed on MoS2 monolayers can be involved in charge storage. One proton of each absorbed water molecule can intercalate/de-intercalate the water bilayers during charging/discharging in the alkaline aqueous electrolyte. For two water molecules are present for every Mo atom, the water bilayers can endow MoS2 monolayers an ultrahigh specific capacitance. In this paper, 1T phase MoS2 nanosheets with three monolayers were synthesized by hydrothermal reaction. It presents a specific capacitance of 1120 F g−1 at a current density of 0.5 A g−1 in KOH. As it is assembled with active carbon into a hybrid supercapacitor, the device has an energy density of 31.64 Wh kg−1 at a power density of 425 W kg−1, and gets a specific capacitance retention of 95.4% after 10,000 cycles at 2 A g−1.
展开▼
机译:众所周知,在中性和酸性含水电解质中,MoS2单层可以通过将阳离子吸附到电极-电解质界面上作为其石墨烯类似物来存储电荷。受其低电导率和电荷存储机制的限制,MoS2单层超级电容器电极的电化学性能不令人满意。据报道,在MoS 2单层上吸收的水双层可以参与电荷存储。每个吸收的水分子的一个质子可以在碱性水溶液电解质的充电/放电过程中插层/去插层水双层。因为每个Mo原子都有两个水分子,所以水双层可以使MoS2单层具有超高的比电容。通过水热反应合成了具有三个单层的1T相MoS2纳米片。它在KOH中的电流密度为0.5 A g -1 sup>时呈现1120 F g -1 sup>的比电容。当它与活性炭组装成混合超级电容器时,该设备的能量密度为425 W kg -1 sup>,能量密度为31.64 Wh kg -1 sup>,并且在2 A g -1 sup>进行10,000次循环后,其比电容保持率为95.4%。
展开▼