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Poly(2,5‐dimercapto‐1,3,4‐thiadiazole) as a Cathode for Rechargeable Lithium Batteries with Dramatically Improved Performance
Author(s) -
Gao Jie,
Lowe Michael A.,
Conte Sean,
Burkhardt Stephen E.,
Abruña Héctor D.
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201103535
Subject(s) - electrolyte , ethylene carbonate , electrochemistry , propylene carbonate , cyclic voltammetry , battery (electricity) , polysulfide , lithium (medication) , dimethyl carbonate , lithium ion battery , cathode , materials science , inorganic chemistry , chemistry , chemical engineering , electrode , organic chemistry , catalysis , medicine , power (physics) , physics , quantum mechanics , engineering , endocrinology
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.