Tandem Chemical Processes for Efficient Purification and Separation of Lithium Salts and Electrolyte Solvents from Spent Batteries

Lithium-ion batteries (LIBs) have become widely used due to the rapid growth of electronic devices and vehicles. However, the resulting waste of these spent batteries pose many risks to the environment. LIBs consist of cathodes, anodes, and electrolytes, where electrolytes typically present many risks due to its potential release of toxic compounds. Current disposal methods of spent electrolytes aggravate environmental and health hazards by generating harmful substances containing chemicals such as fluorine and phosphorus. Thus, these issues must be addressed urgently, and we must find more sustainable recycling methods of spent LIB electrolytes. Herein, we introduce methods to safely recycle spent LIB electrolytes, such as vacuum distillation, precipitation, and sublimation. Some electrolyte recycling processes utilize vacuum distillation. In vacuum distillation, the spent electrolyte is heated and evaporated in a vacuum environment, the volatilized electrolyte is then recovered through condensation. In this process, volatile organic solvents such as ethyl carbonate (EC) and dimethyl carbonate (DMC) are recycled, this promotes sustainability in the recycling economy. Subsequently, precipitation and sublimation, both requiring relatively mild conditions, can deliver high quality lithium salts, as well as electrolyte solvents. By preserving critical materials, these approaches are more environmentally and economically feasible for LIB recycling.