Life cycle assessment of experimental Al-ion batteries for energy storage applications

In this work, the analysis of environmental performance and its coherence with circular economy priorities of different variants of Al-ion battery construction was performed. Al-ion-based batteries can be considered as one of the future alternatives for currently used Li-ion-based cells when the shortage of lithium or cobalt becomes a challenge. All tested batteries were constructed with Al anodes, polypropylene foil separator, polyvinylidene fluoride + N-Methyl-2-pyrrolidone (PVDF+NMP) binder, Al collector and laminated Al foil pouch cell. WO3, Norit and carbon from potato starch (CPS) were used as a cathode material. Saturated solutions of AlCl3 dissolved in diethylene glycol dimethyl ether (DEG) and deep eutectic solvents (DES) originating from bacterial polymer polyhydroxyalkanoate were used as electrolytes. The ReCiPe impact assessment method was used in this analysis. The indicator in this study was ReCiPe Endpoint (H) V1.07 referring to Europe. SimaPro 9.4 software with Ecoinvent 3.8 inventory database were used for all calculations. The analysis included experimental production and assembly of batteries and their end-of-life processing. Based on the performed analysis it was found that the overall weighted impact of each single construction variant of an Al-ion battery is dominated by the use of electricity, no matter which variant is considered since it is related to the electricity mix in Poland and its high dependence on fossil fuels. Overall environmental impact is the smallest for CPS DEG battery, while Norit DEG and CPS DEG variants have slightly higher impacts. The share of end-of-life processing in overall environmental impacts of all analysed variants was found low compared to the Li-ion batteries. This observation indicates the Al-ion batteries as a promising direction of alternative electrochemical devices for energy storage systems while end-of-life processing and circular solution are concerned.