The Use of Tetravalent Sulfur in Molten Chloroaluminate Secondary Batteries

Abstract

A new rechargeable cell Na/Na+ ion normalconductor/SCl3+ in molten AlCl3‐normalNaCl is described. This cell operates at temperatures in the range of 180°–250°C and has an open‐circuit voltage of 4.2V. The discharge process involves the reduction of tetravalent sulfur to the elemental state; sulfur can be further reduced to sulfide. The preferred sodium ion conductor is β″‐alumina. High energy density values, large percent utilization of the active material, and good energy efficiency have been demonstrated. The performance of cells prepared in the discharged and charged states were found to be the same. The number of deep charge/discharge cycles has exceeded 400.

Electrode Kinetics of Organodisulfide Cathodes for Storage Batteries

“…and mechanisms of such oxygen reduction reactions have been extensively studied on various transition metal oxide/carbon or graphite electrodes. All the previous studies proposed that the peroxide intermediate is heterogeneously decomposed on the active surface sites of transition metal oxides, and the reaction was considered to be first-order (3)(4)(5).…”

Sodium/Beta”-Alumina/Organosulfur Batteries Operating at Intermediate Temperatures

“…Accordingly, various efforts have been made to offer alternative high specific energy/power batteries operating at reduced temperatures [ 1,2,3 ]. However, since electrode kinetics and mass transport processes in batteries are thermally activated, lower temperature systems often present a compromise between lower power output, and enhanced reliability, safety, and economic factors.…”

“…). Sodium/organosulfur electrodes present a departure from this tradition in that they are based on a general redox reaction for organic disulfides, RSSR + 2 e = 2 RS 2 Na = Na+ + 2 e Cell rxn: RSSR + 2 Na = 2 NaRS where R is an organic moiety such as CH 3 , c 6 H 5 , CH 3 ocH 2 cH 2 , (1) (2) (3) etc. Among the advantages of such a generic redox couple for energy storage include the ability to control the physical, chemical, and electrochemical properties of the organosulfur species by appropriate choice of the organic R groups.…”

Moderate Temperature Na Cells: IV . and as Rechargeable Cathodes in Molten

“…Typical cycles are shown in Fig. The cycling behavior of NbS2CI 2 and related compounds in basic NaAICI 4 is considerably different from that of S in this melt (7) and the sulfur halides in the acidic NaAICI 4 melt (8,9). The cycling characteristics of NbS2Cl 2 are very similar to that of the in situ synthesized compound of the Na/VS 2 cell.…”