Organosulfur compounds with multiple thiol groups are promising for high gravimetric energy density electrochemical energy storage. We have synthesized a poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT)/poly(3,4-ethylenedioxythiophene) (PEDOT) composite cathode for lithium-ion batteries with a new method and investigated its electrochemical behavior by charge/discharge cycles and cyclic voltammetry (CV) in an ether-based electrolyte. Based on a comparison of the electrochemical performance with a carbonate-based electrolyte, we found a much higher discharge capacity, but also a very attractive cycling performance of PDMcT by using a tetra(ethylene glycol) dimethyl ether (TEGDME)-based electrolyte. The first discharge capacity of the as-synthesized PDMcT/PEDOT composite approached 210 mAh g -1 in the TEGDME-based electrolyte. CV results clearly show that the redox reactions of PDMcT are highly reversible in this TEGDME-based electrolyte. The reversible capacity remained around 120 mAh g -1 after 20 charge/discharge cycles. With improved cycling performance and very low cost, PDMcT could become a very promising cathode material when combined with a TEGDME-based electrolyte. The poor capacity in the carbonate-based electrolyte is a consequence of the irreversible reaction of the DMcT monomer and dimer with the solvent, emphasizing the importance of electrolyte chemistry when studying molecular-based battery materials. The nature of the electrolyte has a dramatic effect on the performance of poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) as a cathode material in lithium-ion batteries. Whereas the use of an ethylene/diethyl carbonate (EC/DEC)-based electrolyte resulted in very poor performance, the use of a tetra(ethylene glycol) dimethyl ether (TEGDME)-based electrolyte dramatically improved the performance in terms of both the discharge capacity and capacity retention (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
|Original language||English (US)|
|Number of pages||6|
|Journal||Chemistry - A European Journal|
|State||Published - May 29 2012|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The financial support from Lockheed Martin and the KAUST-Cornell Center for Energy and Sustainability (KAUST-CU) are greatly appreciated. MAL is supported by a National Defense Science and Engineering Graduate Fellowship. This work is based upon research conducted at the Cornell high energy synchrotron source (CHESS) which is supported by the National Science Foundation and the National Institutes of Health/National Institute of General Medical Sciences under NSF award DMR-0936384. The authors gratefully acknowledge assistance from CHESS staff scientist Dr. Darren Dale, and prior synthesis of the BMTTD molecule by Dr. Jay C. Henderson.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.