Novel Solid Redox Polymerization Electrodes: Electrochemical Properties

Abstract

The generic redox reaction of a class of linear sulfur-containing redox polymerization electrodes can be described as (--SRS--)~ + n (2e-) ~ n (-SRS-) that is, the polymer electrode can be progressively depolymerized, leading ultimately to monomeric anions, as the sulfursulfur bridges between the organic R groups are cleaved during discharge and then the monomer anions can be subsequently reoxidized back to the original polymer during charge. This is the first time the process of electrodepolymerization-electropolymerization has been exploited for energy,storage, establishing a broad class of chemically flexible, low equivalent weight, and inexpensive electrodes for advanced batteries. Electrochemical investigation of a diverse group of novel solid redox polymerization electrodes indicates that these materials are excellent candidates for all-solid-state, thinfilm, energy-storage systems. Some of the advantages offered by the batteries based on these materials include high energy density and rate capability, extensive utilization of positive electrode capacity, ease of fabrication, low cost, and superior reliability, and safety. In addition, these materials are reversible to lithium and sodium (as well as many alkaline earth and transition metals), allowing for a much greater choice of negative electrode materials, in stark contrast to cells based on analogous intercalation compounds. Further, and in particular, a great advantage of redox polymerization electrodes is the ability to alter the physical, chemical, and electrochemical properties of these materials in a very predictable manner through manipulation of various functional groups, electron-withdrawing heteroatoms, and the molecular architecture.

Poly[dithio-2,5-(1,3,4-thiadiazole)] (PDMcT)–poly(3,4-ethylenedioxythiophene) (PEDOT) composite cathode for high-energy lithium/lithium-ion rechargeable batteries

“…For over 15 years, organosulfur-based compounds with multiple thiol groups or disulfide moieties have received attention as potential cathode electroactive materials for lithium/lithiumion rechargeable batteries due to their high theoretical capacity and chemical tunability [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. More importantly, the capability of the thiolate system to release and capture lithium-ions during charge/discharge cycles allows their easy incorporation into the so-called "rocking-chair" type system employed in current lithium-ion battery technologies [16].…”

Improved electrochemical redox performance of 2,5-dimercapto-1,3,4-thiadiazole by poly(3-methoxythiophene)

“…Recently, it has been reported that the redox performance of DMcT can be improved by electrocatalysts such as polyaniline (PAn) and polypyrrol (PPy). For example, Visco et al [3] and Oyama et al [4] reported that PAn can serve as an electrocatalyst to improve the redox kinetics of DMcT at room temperature. Park also reported that the charge-discharge transfer kinetics of DMcT can be enhanced by Ag and Pd nanoparticles [5][6][7].…”

Influence of the preparation procedure on the electrochemical properties of Pani(DMcT-Cu ion)/carbon fiber composites

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] A series of compounds having -SH groups are thought to have a significant potential as energy storage materials, whereby energy exchange occurs according to a reversible polymerization-depolymerization process (2 SH ↔ S-S). 1,2 Among these compounds, 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was first studied by Visco and co-workers 6 as an active cathode material for lithium secondary batteries.…”