Electrolyte
Electrolyte is the ion-conducting medium inside a battery, carrying charged ions between the electrodes while electrons travel through the external circuit. In a rechargeable cell, the ions move in opposite directions during charging and discharging.
Forms and boundaries
An electrolyte can be a liquid solution, a gel or polymer, or an ion-conducting solid. Its physical form does not by itself define the complete cell chemistry: familiar electrode materials can be paired with different electrolyte systems.
The electrolyte is also distinct from the separator. In a conventional lithium-ion cell, the electrolyte provides the ionic path, while the porous separator prevents direct electrical contact between the electrodes and allows ions to pass.
Why it matters
Electrolyte formulation influences ion transport, low-temperature performance, voltage compatibility, interface formation, fast charging, degradation, and safety. The practical result depends on how the electrolyte interacts with both electrodes, the separator, cell construction, temperature, and operating limits.
For electrolyte types, electrode interfaces, and complete-cell trade-offs, see Cell Chemistry & Components.