Litiumioniakku

Litiumioniakku, or lithium-ion battery, is a rechargeable energy storage device that operates by the movement of lithium ions between two electrodes through an electrolyte. The anode is typically graphitic carbon, the cathode is a lithium metal oxide (for example LiCoO2, LiFePO4, or LiNMC variants), and the electrolyte is a lithium salt dissolved in an organic solvent. A separator keeps the electrodes apart to prevent short circuits while allowing ion flow.

During charging, lithium ions migrate from the cathode to the anode while electrons flow in the external circuit; during discharge, the process reverses and electrical energy is delivered. A battery management system monitors voltage, temperature, and state of charge to ensure safety and longevity. Lithium-ion cells are sensitive to high temperatures and overcharging, and proper thermal management and protection circuits are essential.

Performance characteristics include energy density in the range of roughly 150–250 Wh/kg, with higher figures possible for certain chemistries. Power density and cycle life vary by chemistry and use, typically spanning hundreds to over a thousand charge–discharge cycles. Common chemistries include lithium cobalt oxide (LCO), lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), and lithium iron phosphate (LFP), each with trade-offs in energy density, safety, and longevity.

Applications cover a broad spectrum, from portable electronics to electric vehicles and stationary energy storage. Manufacturing requires strict quality controls and clean production environments, and end-of-life recycling is important due to valuable and hazardous materials. Environmental and social considerations drive ongoing improvements in materials sourcing, recycling technologies, and safety standards.