Environmental Life-Cycle Assessment

For our final project in Environmental Life-Cycle Assessment, our four-person team conducted a cradle-to-grave comparison of four EV battery chemistries — Lithium Iron Phosphate (LFP), Nickel Manganese Cobalt (NMC), Solid-State (SSB), and Sodium-Ion (SIB) — across production, transportation, use, recycling, and second-life energy storage. We used two functional units in parallel: one kWh of nominal capacity (the standard comparison) and one kWh of electricity delivered over the battery's full service life. The dual unit matters because chemistries with longer cycle life get penalized under capacity-based comparisons even when they consume less material per unit of energy actually delivered.

Across five impact categories — cumulative energy demand, global warming potential, acidification, eutrophication, and photochemical ozone — production dominated, with the cathode slurry alone driving 78–92% of CED. LFP showed the lowest impacts under current conditions, while solid-state had the highest production burden due to energy-intensive electrolyte sintering and lithium-metal anode fabrication. Sodium-ion looked unfavorable on a per-kWh-capacity basis because its recycling infrastructure does not yet exist, but became competitive once durability was credited under the lifetime functional unit.

The decisive lever was second-life deployment in stationary energy storage, which extended useful service by roughly 163% on average and reduced per-kWh impacts by ~62% across all chemistries. A sensitivity analysis showed that if SSB and SIB reach the longer cycle lives their developers project, they out-perform LFP across nearly every category. The work makes the case that battery sustainability is determined less by chemistry choice than by lifetime management — manufacturing efficiency, recycling infrastructure, and whether retired packs are routed to second-life storage before recycling.