High-voltage and wide temperature aqueous supercapacitors aided by deep eutectic solvents

作者：Zhang, Zhong Jie^*; Chen, Xiang Ying; Feng, Hua Jie^*

来源：Journal of Electroanalytical Chemistry, 2022, 908: 116082.

DOI：10.1016/j.jelechem.2022.116082

• High voltage
• Wide temperature
• Deep eutectic solvent
• Density functional theory
• Aqueous supercapacitor

For water supercapacitors, how to realize high voltage and wide temperature range operation is of great theoretical and practical significance. In this work, introducing a deep eutectic solvent (DES) composed of choline chloride (ChCl, as hydrogen bond acceptor) and ethylene glycol (EG, as hydrogen bond donor) into H2O (as cohydrogen bond donor) produces DES-H2O electrolyte. Furthermore, density functional theory (DFT) can design and verify the DES system. The experimental results show that the molar ratio of DES plays a decisive role in the solvent structure and supercapacitor performance. When the molar ratio of ChCl, EG and H2O is 1:2:2, the DES structure is the most stable, the total energy is the largest (49.93 eV), also exhibiting the high voltage window of 2.4 V, and the wide temperature range of - 40 to 80 degrees C. In the meanwhile, superior capacitive performance also occurs with specific capacity of 202 F g(-1), energy density of 40.3 Wh kg(-1) and cyclability (98.51% after 10,000 cycles) The present DES-H2O electrolyte has the advantages of low price, easy synthesis, good water resistance and high electrochemical performance, which makes it have large application potential in the field of supercapacitors.

• 单位
  海南师范大学