Synthesis and evaluation of polythiocyanogen (SCN) x as a rechargeable lithium-ion battery electrode material

Abstract

Polythiocyanogen, (SCN) x , is a promising lithium-ion battery electrode material due to its high theoretical capacity (462 mAh g −1), safe operation, inexpensive raw materials, and a simple and less energy-intensive manufacturing process. The (SCN) x was prepared from the solution of trithiocyanate (SCN) 3 − in methylene dichloride (MDC), which was prepared by electrochemical oxidation of ammonium thiocyanate (NH 4SCN) in a two-phase electrolysis medium of 1.0 M NH 4SCN in 0.50 M H 2SO 4 + MDC. The (SCN) 3 − underwent auto catalytic polymerization to (SCN) x during MDC removal. Battery electrodes with (SCN) x as the active material were prepared, and tested in Swagelok cells using lithium foil as the counter and reference electrode. The cells delivered capacities in the range of 200–275 mAh g −1 at the discharge–charge rate of 0.2 C. The cells were tested up to 20 cycles and showed repeatable performance with a coulombic efficiency of 97% at the 20th cycle. The results presented here indicate that (SCN) x is a promising lithium-ion battery electrode-material candidate for further studies.