Improving rate capability and reducing over-potential of lithium-oxygen batteries through optimization of Dimethylsulfoxide-N/N-dimethylacetamide mixed electrolyte. (20th July 2017)

• Record Type: Journal Article
• Authors: Chen, Chunguang; Li, Liangyu; Su, Junming; Zhang, Congcong; Chen, Xiang; Huang, Tao; Yu, Aishui
• Is Part Of: Electrochimica acta. Volume 243(2017)
• Page Start: 357
• Page End: 363
• Publication Date: 2017-07-20
• Subjects: DMSO-based electrolyte -- Lithium-oxygen batteries -- Mixed electrolyte -- N, N-dimethylacetamide -- Over-potential -- Rate capability; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.05.074
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Although dimethylsulfoxide (DMSO) solvent has been widely researched in rechargeable lithium-oxygen (Li-O2 ) batteries, high polarization voltage and low rate capability limited its application. In this work, we reported a DMSO-based electrolyte system by adding N, N-dimethylacetamide (DMA) to adjust its physical and electrochemical properties. The ionic conductivity, viscosity, oxygen solubility and diffusion coefficient of the mixed electrolytes as well as their electrochemical performance in Li-O2 batteries are researched. The electrochemical tests show that the optimized DMSO/DMA volume ratio is 30 to 70 based on the rate performance and polarization voltage of the cell. Compared with that of the pure DMSO-based electrolyte, the cell with the mixed electrolyte shows improved rate capability and reduced charge-discharge over-potential. When increasing current density from 0.2 to 0.5 mA cm −2, the capability retention improves from 32% to 59%. Meanwhile, the charge-discharge voltage gap drops from 1.4V to 0.9V at a current density of 0.2 mA cm −2 . The improved electrochemical performance could be attributed to low viscosity, high oxygen solubility and diffusion coefficient as well as the low charge-transfer resistance with the mixed electrolyte.