A lithium-ion battery is a type of rechargeable battery that uses lithium ions as the primary component of its electrolyte. During the discharge cycle, lithium atoms in the anode are ionized and separated from their electrons. The lithium ions move from the anode and pass through the electrolyte until they reach the cathode, where they recombine with their electrons and electrically neutralize.

Structure of Li-ion battery

Li-ion Cell Structure

While the structure of a Li-ion battery depends on the design and make of the individual product, the basic structure of a lithium-ion battery typically consists of the following components:

• Anode: The anode is the negative electrode of the battery and is usually made of carbon. During charging, lithium ions move from the cathode to the anode, where they are stored in the form of lithium intercalation compounds.
• Cathode: The cathode is the positive electrode of the battery and is usually made of metal oxides such as lithium cobalt oxide, lithium manganese oxide, or lithium iron phosphate. During discharging, lithium ions move from the anode to the cathode, producing an electrical current.
• Separator: The separator is a thin membrane that separates the anode and the cathode, preventing them from coming into direct contact with each other while allowing the flow of lithium ions.
• Electrolyte: The electrolyte is a solution that allows the flow of lithium ions between the anode and cathode. It is typically a lithium salt dissolved in an organic solvent.
• Current Collectors: These are conductive materials, typically made of copper or aluminum, that collect the electrical current produced by the battery and conduct it to the external circuit.

The anode, cathode, and separator are all rolled up into a cylinder or stacked in a pouch, and then immersed in the electrolyte solution. The current collectors are attached to the ends of the rolled or stacked components, providing the means to connect the battery to external devices or circuits.

Working of Li-Ion Battery

A lithium-ion battery works by the movement of lithium ions between the anode and cathode through the electrolyte. During charging, a voltage is applied to the battery, causing a flow of electrons from the power source to the battery. This causes the lithium ions in the electrolyte to move toward the anode, where they are stored in the form of lithium intercalation compounds. At the same time, lithium ions are released from the cathode and travel through the electrolyte toward the anode, creating an electrical current that can be used to power external devices or vehicles. During discharging, the stored lithium ions in the anode move back to the cathode through the electrolyte, producing an electrical current that can be used to power devices or vehicles. This cycle of charging and discharging continues until the capacity of the battery is depleted, at which point the battery must be recharged. 

Applications:

Applications of Li-Ion Battery

Lithium-ion batteries have a wide range of applications which keeps increasing by the day, due to their high energy density, low self-discharge rate, and long cycle life. Some of the common applications of lithium-ion batteries are:

• Portable Electronics: Lithium-ion batteries are widely used in portable electronic devices such as smartphones, laptops, tablets, and digital cameras due to their lightweight and long-lasting power.
• Electric Vehicles: Lithium-ion batteries are commonly used in electric vehicles due to their high energy density and ability to provide a lot of power quickly. They are also more environmentally friendly than traditional gasoline-powered vehicles.
• Energy Storage: Lithium-ion batteries are used in energy storage systems for homes, businesses, and power grids. These systems help to store renewable energy from sources such as solar and wind power, making it available when needed and facilitating the synchronization of different power generation methods. 
• Medical Devices: Lithium-ion batteries are used in medical devices such as pacemakers, defibrillators, and hearing aids due to their long life and reliable performance.
• Aerospace: Lithium-ion batteries are used in spacecraft and satellites due to their lightweight, high power density, and ability to function in the extreme conditions of space.
• Power Tools: Lithium-ion batteries are used in cordless power tools such as drills, saws, and sanders because they are lightweight and provide long-lasting power.
• Emergency Backup Power: Lithium-ion batteries can be used as a backup power source during power outages or emergencies, providing a reliable source of power for critical devices such as medical equipment, communications, and lighting.
• Military: Lithium-ion batteries are used in military applications such as unmanned aerial vehicles (UAVs) and communication equipment due to their lightweight, long-lasting power, and ability to function in extreme environments.
• Wearables: Lithium-ion batteries are used in wearable technology such as smartwatches and fitness trackers because they are small, lightweight, and provide long battery life.

Click here to learn more about the difference between Lithium-Ion and Solid-State Batteries.