CR2025 Battery

An electric battery is essentially a source of DC electrical energy. It converts stored chemical energy into electrical energy through an electrochemical process. This then provides a source of electromotive force to enable currents to flow in electric and electronic circuits. A typical battery consists of one or more voltaic cells. 

The fundamental principle in an electrochemical cell is spontaneous redox reactions in two electrodes separated by an electrolyte, which is a substance that is ionic conductive and electrically insulated.

A CR2025 battery is a 3V lithium-metal-based button cell that is used in a wide range of applications like computer motherboards, car key fobs, watches, calculators, PDAs, electronic organizers, garage door openers and toys.

Dimensions, Weight and Capacity of CR2025 Battery

CR2025 batteries (20 mm x 2.5 mm) have a nominal diameter of 20 millimeters. The overall height is 2.5 millimeters. Its weight is only 2.6 grams.

Because the CR2025 batteries are chemically very stable, they still have 90% of their original capacity even after 10 years. The stability is the result of the combination of lithium and manganese dioxide. The long-lasting function of these batteries has been verified at all operating temperatures under low-load discharge conditions.

Lithium Metal Batteries

Lithium-based primary cells are batteries that have metallic lithium as an anode. These types of batteries are also referred to as lithium-metal batteries. Note that disposable primary lithium batteries must be distinguished from secondary lithium-ion or lithium-polymer, which are rechargeable batteries. Lithium-ion batteries do not contain metallic lithium. 

Primary lithium batteries have the lowest self-discharge rate hence the longest available shelf time, up to 10 years, and in temperatures up to 70. The first letter in the IEC standard system identifies the battery’s chemical composition. C is for lithium metal batteries (as CR2032). The characteristics that make lithium an exceptional electrode material for high energy density batteries include low electrode potential and very high conductivity. It is soft and malleable and can be extruded into thin foils.

They may be classified in several ways, but one convenient method is by the cathode material and voltage. Using an iron disulfide cathode gives a battery with a nominal voltage of 1.5 volts. This cell is used for high-performance AA batteries. Most other lithium batteries are 3.0 volt systems using cathodes comprising either solids (manganese dioxide or carbon monofluoride) or highly toxic liquids (sulfur dioxide or thionyl chloride).

Characteristics of CR2025 Battery

To compare and understand the capability of each battery, some important parameters are characteristic of each battery, also within a type of battery. These parameters are a reference when a battery is needed, and specific qualities are required since batteries are used in all types of devices and for infinite purposes.

Chemistry of Lithium Metal Batteries

In simple terms, each battery is designed to keep the cathode and anode separated to prevent a reaction. The stored electrons will only flow when the circuit is closed. This happens when the battery is placed in a device and the device is turned on.

When the circuit is closed, the stronger attraction for the electrons by the cathode (e.g. manganese dioxide in primary lithium batteries) will pull the electrons from the anode (e.g. lithium metal) through the wire in the circuit to the cathode electrode. This battery chemical reaction, this flow of electrons through the wire, is electricity.

If we go into detail, batteries convert chemical energy directly to electrical energy. For example, chemical energy can be stored in Zn or Li, which are high-energy metals because they are not stabilized by d-electron bonding, unlike transition metals.

Even though a wide range of types of batteries exists with different combinations of materials, all of them use the same principle of the oxidation-reduction reaction. In an electrochemical cell, spontaneous redox reactions take place in two electrodes separated by an electrolyte, which is a substance that is ionic conductive and electrically insulated. The redox reaction is a chemical reaction that produces a change in the oxidation states of the atoms involved. Electrons are transferred from one element to another. As a result, the donor element, which is the anode, is oxidized (loses electrons), and the receiver element, the cathode, is reduced (gains electrons).

In a primary lithium battery, the negative electrode is metallic lithium, and the positive electrode is high-density manganese dioxide (MnO₂). The electrolyte in Li/MnO₂ cells is an organic solvent mixture into which an alkali metal salt is dissolved.  Li⁺ ions go into the solution and diffuse through the electrolyte and separator to the cathode. Electrons travel through the external circuit and arrive at the cathode where MnO₂, Li⁺ ions, and electrons combine. The MnO₂ is reduced from the tetravalent to the trivalent state. The solid discharge reaction product remains in the cathode. No gases are evolved during discharge to cause a pressurized condition

The half-reactions are:

Mn^IVO_2(s) + Li⁺ + e⁻ → Mn^IIIO₂(Li⁺) 

Li_(s) → Li⁺ + e⁻ 

Overall reaction:

Li_(s) + Mn^IVO_2(s) ⇌ Mn^IIIO₂(Li⁺) [E° = +3.19 V]

Applying this battery chemistry to the real world, the electrons generated during the reaction are used to power devices when the circuit is closed.

Advantages and Disadvantages of Lithium Metal Batteries

Other Types of Batteries

The following list summarizes notable electric battery types composed of one or more electrochemical cells. Four lists are provided in the table. The first list is a battery classification by size and format. Then, the primary (non-rechargeable) and secondary (rechargeable) cell lists are lists of battery chemistry. The third list is a list of battery applications. The final list is a list of different battery voltages.