NOVEL SOLID REDOX POLYMERIZATION ELECTRODES - ELECTROCHEMICAL PROPERTIES

The generic redox reaction of a class of linear sulfur-containing redox polymerication electrodes can be described as (-SRS-)n + n (2e-) reversible n (-SRS-) that is, the polymer electrode can be progressively depolymerized, leading ultimately to monomeric anions, as the sulfur-sulfur 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, thin-film, 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.