Lithium-ion batteries power the lives of millions of people each day. From laptops and cell phones to hybrids and electric vehicles, this technology is growing in popularity due to its light weight, high energy density, and ability to recharge.

What is a lithium-ion battery?

Lithium-ion battery is the most popular rechargeable battery chemistry used today. Lithium-ion batteries power the devices we use every day, like our mobile phones and electric vehicles.

Lithium-ion batteries consist of single or multiple lithium-ion cells, along with a protective circuit board. They are referred to as batteries once the cell, or cells, are installed inside a device with the protective circuit board.

What are the components of a lithium-ion battery?

• Electrodes: The positively and negatively charged ends of a cell. Attached to the current collectors
• Anode: The negative electrode
• Cathode: The positive electrode
• Electrolyte: A liquid or gel that conducts electricity
• Current collectors: Conductive foils at each electrode of the battery that are connected to the terminals of the cell. The cell terminals transmit the electric current between the battery, the device and the energy source that powers the battery
• Separator: A porous polymeric film that separates the electrodes while enabling the exchange of lithium ions from one side to the other

How Lithium-ion Batteries Work?

In a lithium-ion battery, lithium ions (Li+) move between the cathode and anode internally. Electrons move in the opposite direction in the external circuit. This migration is the reason the battery powers the device—because it creates the electrical current.

While the battery is discharging, the anode releases lithium ions to the cathode, generating a flow of electrons that helps to power the relevant device. 

When the battery is charging, the opposite occurs: lithium ions are released by the cathode and received by the anode.

THE BASICS

A Lithium-ion battery is made up of an anode, cathode, separator, electrolyte, and two current collectors (positive and negative). The anode and cathode store the lithium. The electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive current collector.  The electrical current then flows from the current collector through a device being powered (cell phone, computer, etc.) to the negative current collector. The separator blocks the flow of electrons inside the battery.

History and Development of Lithium-Ion Battery:

Lithium-ion (Li-ion) batteries were first conceptualized in the 1970s. British chemist M. Stanley Whittingham discovered that lithium could be used as a battery’s anode material, leading to the development of the first rechargeable lithium battery. However, these early batteries were not commercially viable due to safety issues. In the 1980s, Akira Yoshino, a Japanese chemist, created a safer, more practical Li-ion battery using a carbon-based material instead of lithium metal for the anode. Sony commercialized Yoshino’s battery in 1991, marking the beginning of the widespread use of Li-ion batteries in consumer electronics and later in electric vehicles (EVs).

Basic Working Principle of Lithium-ion battery:

A lithium-ion battery operates by the movement of lithium ions between the anode and cathode through an electrolyte. During discharge, lithium ions move from the anode to the cathode, releasing energy. During charging, an external power source drives the lithium ions back to the anode, storing energy for later use. The flow of electrons through an external circuit provides the electric current.

Chemical Reactions Involved:

Inside a lithium-ion battery, oxidation-reduction (Redox) reactions take place.

Reduction takes place at the cathode. There, cobalt oxide combines with lithium ions to form lithium-cobalt oxide (LiCoO₂). The half-reaction is:

CoO₂ + Li⁺ + e^– → LiCoO₂

Oxidation takes place at the anode. There, the graphite intercalation compound LiC₆ forms graphite (C₆) and lithium ions. The half-reaction is:

LiC₆ → C₆ + Li⁺ + e^–

Here is the full reaction (left to right = discharging, right to left = charging):

LiC₆ + CoO₂ ⇄ C₆ + LiCoO₂

Types of Lithium-Ion Batteries:

1. Lithium Cobalt Oxide (LiCoO2): Commonly used in smartphones, laptops, and digital cameras. Known for high energy density but limited lifespan and thermal stability.
2. Lithium Iron Phosphate (LiFePO4): Known for safety and long cycle life. Used in electric vehicles and stationary energy storage.
3. Lithium Manganese Oxide (LiMn2O4): Offers high thermal stability and safety. Commonly used in medical devices and power tools.
4. Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2 or NMC): Balances energy density, lifespan, and safety. Widely used in electric vehicles and power tools.
5. Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2 or NCA): Offers high energy density and long lifespan. Used in electric vehicles and grid storage.

CHARGE/DISCHARGE

While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other. When plugging in the device, the opposite happens: Lithium ions are released by the cathode and received by the anode.

ENERGY DENSITY VS. POWER DENSITY:

The two most common concepts associated with batteries are energy density and power density. Energy density is measured in watt-hours per kilogram (Wh/kg) and is the amount of energy the battery can store with respect to its mass. Power density is measured in watts per kilogram (W/kg) and is the amount of power that can be generated by the battery with respect to its mass. To draw a clearer picture, think of draining a pool. Energy density is similar to the size of the pool, while power density is comparable to draining the pool as quickly as possible. 

FAQs:

Q.1 What is the use of lithium-ion battery ?

Ans. Lithium-ion (Li-ion) batteries are used in many products such as electronics, toys, wireless headphones, handheld power tools, small and large appliances, electric vehicles and electrical energy storage systems.

Q.2 What are the advantages of a lithium-ion battery?

Below, we spotlight the benefits of lithium ion batteries.

• High energy density. When it comes to energy density, lithium ion batteries are top performers. …
• Lightweight. …
• Long lifespans. …
• Good long-term performance. …
• Temperature tolerant. …
• Low self-discharge. …
• Fast charge times. …
• Customisable technology.

Q.3 What is the purpose of lithium ion battery?

Ans. Lithium-ion batteries power the lives of millions of people each day. From laptops and cell phones to hybrids and electric cars, this technology is growing in popularity due to its light weight, high energy density, and ability to recharge.

Q.4 How is lithium made?

Ans. Lithium is found in rock ores, which are mined and crushed, or in briny water, where it can be extracted using evaporation. Lithium is an essential component of clean energy technologies, from electric vehicles (EVs) to the big batteries used to store electricity at power plants.

Q.5 What are the disadvantages of lithium-ion batteries?

• 3.1 Relatively Higher Cost. The utility of rare metals in lithium-ion batteries increases the cost of raw materials and refining processes. …
• 3.2 Slightly Heavier Weight. …
• 3.3 Repair and Maintenance Challenges. …
• 3.4 Safety concerns.