Lithium-ion battery
A rechargeable battery in which lithium ions shuttle between a graphite anode and a metal-oxide or phosphate cathode; the dominant chemistry for EVs and grid storage.
A lithium-ion battery stores energy by intercalating lithium ions into the crystal lattice of its electrodes. During discharge, ions move from the anode (usually graphite, sometimes with silicon additive) through a liquid electrolyte (LiPF6 in organic carbonates) to the cathode, while electrons flow through the external circuit. The cathode chemistry largely defines the cell: LFP, NMC, NCA or LMO.
Typical nominal voltage: NMC 3.6–3.7 V; LFP 3.2 V
Typical cell-level gravimetric energy density ranges from about 160–205 Wh/kg for LFP to 250–300 Wh/kg for high-nickel NMC. Round-trip efficiency is 90–95% at cell level and roughly 85–90% for a complete grid system including inverter and auxiliary loads. Pack prices fell from over 1,000 USD/kWh in 2010 to about 115 USD/kWh in 2024 (BloombergNEF), with stationary LFP packs cheaper still, which drove the boom in EVs and BESS.
Main limitations are thermal runaway risk (mitigated by chemistry choice, cell spacing and battery management systems), calendar and cycle ageing, and dependence on lithium, nickel, cobalt and graphite supply chains. See the battery storage technology page.
Related terms
All terms →- LFP (Lithium Iron Phosphate)
A lithium-ion cathode chemistry (LiFePO4) prized for safety, long cycle life and low cost, at the expense of lower energy density than nickel-based cells.
- NMC (Nickel Manganese Cobalt)
A family of lithium-ion cathodes (LiNixMnyCozO2) offering high energy density, widely used in long-range electric vehicles.
- Sodium-ion battery
A rechargeable battery analogous to lithium-ion but using abundant sodium ions, trading energy density for lower material cost and better cold performance.
- Cycle life
The number of full charge-discharge cycles a battery can deliver before its capacity falls to a defined end-of-life threshold, usually 70–80% of rated capacity.
- Energy density
The amount of energy stored per unit mass (specific energy, Wh/kg or MJ/kg) or per unit volume (Wh/L or MJ/L) of a fuel or storage medium.
- BESS (Battery Energy Storage System)
A complete grid- or site-connected battery installation, including cells, battery management, power conversion, thermal management and controls.