what happens to a battery when it is "recharged"
When a battery is recharged, a chemical reaction takes place within the battery that replenishes its stored energy. The specific behavior of a battery during the recharging process depends on its type (e.g., lead-acid, nickel-cadmium, lithium-ion) and design.
To understand what happens during the recharging process, let's consider a standard rechargeable battery like a lithium-ion battery commonly used in electronic devices:
1. Discharging Phase: When you use a battery in a device, such as a smartphone, tablet, or laptop, it starts to discharge. During this process, the lithium ions within the battery move from the negative electrode (anode) to the positive electrode (cathode), generating electrical energy that powers the device.
2. Recharging Phase: When you connect a rechargeable battery to a power source, such as a charger, the process reverses. The charger sends an electric current through the battery in the opposite direction. This current causes the lithium ions to move from the cathode back to the anode, effectively "recharging" the battery.
3. Electrochemical Reaction: The recharging process involves a complex electrochemical reaction. Lithium-ion batteries typically utilize a lithium compound, such as lithium cobalt oxide, on the cathode side and carbon (graphite) on the anode side. During recharging, lithium ions from the cathode intercalate (insert) into the graphite anode, storing potential energy.
4. Restoration of Battery Capacity: As lithium ions move back to the anode, the battery's energy storage capacity is restored. The recharging process continues until the lithium ions return to their original positions, allowing the battery to hold its maximum charge again.
It's important to note that the rechargeability of a battery has limitations. Over time and repeated recharging cycles, batteries may experience a decrease in their overall capacity. This reduction in capacity is due to various factors, including chemical reactions, electrode degradation, and aging of the battery's components.
In summary, when a battery is recharged, an electrochemical reaction occurs, allowing the movement of ions between the electrodes. This process replenishes the battery's stored energy, enabling it to provide power for future use.