Lithium-Ion Electrochemistry
All modern EV batteries use lithium-ion chemistry as their foundation. A lithium-ion cell has three key components: a cathode (positive electrode), an anode (negative electrode), and an electrolyte through which lithium ions migrate. During discharge (powering the motor), lithium ions move from the anode — typically graphite — through the liquid electrolyte to the cathode, which is a lithium metal oxide compound. The most common cathode chemistries in EVs today are NMC (nickel manganese cobalt oxide), NCA (nickel cobalt aluminum oxide), and LFP (lithium iron phosphate). NMC and NCA offer high energy density — critical for long range — while LFP trades some energy density for significantly longer cycle life, better thermal stability, and lower cost. Tesla switched its standard-range vehicles to LFP in 2021. The cathode chemistry choice is one of the biggest drivers of an EV's range, cost, longevity, and safety profile. Cells operate between ~2.5V (fully discharged) and ~4.2V (fully charged), with most battery management systems (BMS) keeping cells between 20% and 80% SoC during daily use to maximize lifespan.