Stepwise Cycling Process for Natural Gas Decomposition Driven by Low-Dissociation-Voltage Molten ZnCl2–LiCl–KCl Electrolysis

Molten metal halide salt electrolysis offers a promising approach for the efficient conversion of natural gas under mild conditions. However, the dissociation voltages of alkali or alkaline earth halides are typically high, causing high electrical energy cost. Herein, we report the use of ZnCl ₂ to replace NaCl dissolved in molten LiCl–KCl to decrease the operating voltage by ~ 2 V, remarkably reducing electrical consumption. In addition, this work features a stepwise cyclic process to decouple the electrolysis, the chlorination and the dechlorination, and reports detailed results on the molten ZnCl ₂ –LiCl–KCl electrolysis and the dechlorination of chlorinated methanes and chlorinated ethanes with molten Zn. Overall, it is a promising approach for efficient decomposition of natural gas under moderate temperatures (less than 600 ºC) and also at reduced applied voltages, substantially improving the practicality of the system.