Zhou Ruihua, Wei Sufeng, Liu Yan, Gao Nan, Wang Guoyong, Lian Jianshe, Jiang Qing
Key Laboratory of Automobile Materials, Department of Materials Science and Engineering, Jilin University, Changchun, 130025, PR China.
Key Laboratory of Advanced Structural Materials, Changchun University of Technology, Changchun, 130012, PR China.
Sci Rep. 2019 Mar 8;9(1):3980. doi: 10.1038/s41598-019-40672-w.
It is well-known that in neutral and acidic aqueous electrolytes, MoS 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 MoS monolayer supercapacitor electrode is not satisfactory. It is reported here that water bilayers absorbed on MoS 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 MoS monolayers an ultrahigh specific capacitance. In this paper, 1T phase MoS nanosheets with three monolayers were synthesized by hydrothermal reaction. It presents a specific capacitance of 1120 F g at a current density of 0.5 A g in KOH. As it is assembled with active carbon into a hybrid supercapacitor, the device has an energy density of 31.64 Wh kg at a power density of 425 W kg, and gets a specific capacitance retention of 95.4% after 10,000 cycles at 2 A g.
众所周知，在中性和酸性水性电解质中，与石墨烯类似，二硫化钼单层可以通过阳离子吸附在电极 - 电解质界面上存储电荷。受其低电导率和电荷存储机制的限制，二硫化钼单层超级电容器电极的电化学性能并不理想。本文报道，吸附在二硫化钼单层上的水双层可参与电荷存储。在碱性水性电解质中充电/放电过程中，每个吸附水分子的一个质子可嵌入/脱出该水双层。由于每个钼原子存在两个水分子，水双层可赋予二硫化钼单层超高的比电容。本文通过水热反应合成了具有三个单层的1T相二硫化钼纳米片。在氢氧化钾中，其在电流密度为0.5 A g时呈现出1120 F g的比电容。当它与活性炭组装成混合超级电容器时，该器件在功率密度为425 W kg时的能量密度为31.64 Wh kg，并且在2 A g下循环10000次后比电容保持率为95.4%。
