Lian Ziyu, Mao Xiling, Song Yi, Yao Kaihua, Zhang Ruifeng, Yan Xinyu, Li Mengwei
School of Instrument and Electronics, North University of China, Taiyuan 030051, China.
Nanomaterials (Basel). 2024 Dec 17;14(24):2029. doi: 10.3390/nano14242029.
In order to broaden the working voltage (1.23 V) of aqueous supercapacitors, a high-performance asymmetric supercapacitor with a working voltage window reaching up to 2.1 V is assembled using a nanorod-shaped molybdenum trioxide (MoO) negative electrode and an activated carbon (AC) positive electrode, as well as a sodium sulfate-ethylene glycol ((NaSO-EG) electrolyte. MoO electrode materials are fabricated by adjusting the hydrothermal temperature, hydrothermal time and solution's pH value. The specific capacity of the optimal MoO electrode material can reach as high as 244.35 F g at a current density of 0.5 A g. For the assembled MoO//AC asymmetric supercapacitor with a voltage window of 2.1 V, its specific capacity, the energy density, and the power density are 13.52 F g, 8.28 Wh kg, and 382.15 W kg at 0.5 A g, respectively. Moreover, after 5000 charge-discharge cycles, the capacity retention rate of the device still reaches 109.2%. This is mainly attributed to the small particle size of MoO nanorods, which can expose more electrochemically active sites, thus greatly facilitating the transport of electrolyte ions, immersion at the electrolyte/electrolyte interface and the occurrence of electrochemical reactions.
为了拓宽水系超级电容器的工作电压（1.23 V），采用纳米棒状三氧化钼（MoO）负极、活性炭（AC）正极以及硫酸钠-乙二醇（（NaSO-EG））电解质组装了工作电压窗口高达2.1 V的高性能不对称超级电容器。通过调节水热温度、水热时间和溶液pH值来制备MoO电极材料。在电流密度为0.5 A g时，最佳MoO电极材料的比电容可高达244.35 F g。对于组装的电压窗口为2.1 V的MoO//AC不对称超级电容器，在0.5 A g时其比电容、能量密度和功率密度分别为13.52 F g、8.28 Wh kg和382.15 W kg。此外，经过5000次充放电循环后，该器件的容量保持率仍达到109.2%。这主要归因于MoO纳米棒的粒径较小，能够暴露出更多的电化学活性位点，从而极大地促进了电解质离子的传输、在电解质/电极界面的浸润以及电化学反应的发生。
