Like all batteries, a Li Batt stores chemical energy and converts it to electrical energy to provide power. Specifically, a Li Batt is a type of rechargeable battery that uses the reversible reduction of lithium ions to store energy: the anode (-) carries positively charged particles via an electrolyte (a liquid or gel) through a separator (inside the battery) to the cathode (+); the movement of these particles creates energy (electrical current) in the anode (-), which flows through the device being powered, and back into the cathode (+), beginning the cycle again.
Unlike previous generations of “traditional” batteries[i] – whose anodes/cathodes used combinations of metals including lead (anodes/cathodes) and acid (electrolyte) to move particles (electrons) – Li Batts typically use graphite/copper (anode), a metallic lithium oxide (cathode), and a lithium-salt-&-solvent solution (electrolyte) to move particles (lithium ions).
[i] E.g. Sealed Lead-Acid (SLA) batteries, Absorbent Glass Mat (AGM) batteries, Gel batteries.