Life Cycle Assessment Studies on Next-Generation Secondary Batteries for Electric Vehicles: Review

This study critically reviews life cycle assessment (LCA) studies on next-generation secondary batteries (rechargeable battery) for electric vehicle (EV) applications, focusing on lithium-ion batteries (LIBs) with silicon nanowire/nanotube (SiNW/SiNT) anodes, all-solid-state batteries (ASSBs), and lithium–sulfur (Li–S) batteries. The reviewed work is analyzed in terms of how the goal and scope of the LCA are defined, how life cycle inventories (LCIs) are constructed, and how the environmental impacts are assessed. The energy-intensive manufacturing process of next-generation secondary batteries is a factor in their higher environmental impact compared to conventional LIB manufacturing processes. This suggests that the superiority of LCI can vary depending on the method used to construct the LCI and the assumptions surrounding the manufacturing process. Moreover, most LCA works of these emerging battery systems employ heterogeneous functional units, rely on laboratory-scale studies at low technology readiness levels using bottom-up inventory modelling, and are restricted to cradle-to-gate system boundaries. These characteristics hinder a consistent comparison of environmental impacts across battery chemistries, resulting in substantial uncertainty due to limited data quality. Based on these findings, the paper underlines the need for partial standardization of functional units and system boundaries, systematic inclusion of the use phase, and more rigorous sensitivity and scenario analyses in LCAs of next-generation secondary batteries. It further proposes that future studies adopt top-down LCI construction approaches in which desirable LCA outcomes are first set as targets, and the process conditions and LCI datasets required to meet these targets are subsequently inferred in a backward manner.