Essay On Electric Battery

An electric battery is a device consisting of two or more than two electrochemical cells that convert stored chemical energy into electrical energy. Each cell comprises of a positive terminal which is called as cathode, and a negative terminal which is called as anode. Flow of current out of the battery is accomplished by the movement of ions (present in the electrolytes) between the electrodes and terminals.

Primary (single-use or "disposable") batteries are used once and discarded; the electrode materials are irreversibly changed during discharge. Alkaline batteries are common examples of disposable batteries and they are used for flashlights and a multitude of portable devices. Secondary (rechargeable batteries) can be discharged and recharged

A typical battery consists of some number of voltaic cells, in which each cell consists of two half-cells connected in series by a conductive electrolyte that consists of positive and negative ions. One half-cell includes electrolyte and the negative electrode, the electrode to which anions (negatively charged ions) migrate; the other half-cell includes electrolyte and the positive electrode to which cations (positively charged ions) migrate. Battery is powered by the redox reaction. During charging, Cations are reduced (electrons are added) at the cathode, while anions are oxidized (electrons are removed) at the anode during discharge. Some cells use different electrolytes for each half-cell. The presence of separator makes it possible for the ions to flow between half-cells, by preventing the mixing of electrolytes.

Each half-cell has an electromotive force (or emf), determined by its ability to drive electric current from the interior to the exterior of the cell. The net emf of the cell is the difference between the emf of its half-cells. Thus, if the electrodes have emfs and , then the net emf is ; The net emf can also be defined as the difference between the reduction potentials of the