Scientists explore the design of miniature batteries: capable of storing up to 4 times energy

2023-12-28

One of the forefront of battery research is the use of structural components to store energy. At present, this idea has been used as a way to reduce weight and is being equipped in electric vehicles and soldier equipment. Now, scientists are applying this concept to miniature batteries, which are lightweight enough for insects to carry and have an energy density four times that of traditional batteries.

This study was conducted by engineers from the University of Pennsylvania who are researching new battery designs that are compact and durable enough to power smaller wearable and electronic devices. In order to maintain the operation of these types of devices, batteries need to be protected from impact, water, and oxygen damage, but this involves increasing their weight and size of the casing, which is of no help to their electrochemical performance.

To overcome this limitation, scientists have reimagined the typical design of miniature batteries. These devices typically have ultra-thin electrodes that allow for rapid transfer of electrons and ions, but this ultra-thin shape limits the amount of chemicals they can contain, thus limiting the amount of energy they can store.

At the cathode of a battery, it is usually composed of powdered particles that are compressed together to form a porous structure with air gaps, which affects the speed of ion movement in the battery. Scientists have overcome this problem by developing a much denser cathode material that can be directly "electroplated" onto thin metal foil, which can also serve as a casing.

Research leader James Pikul said, "We have essentially manufactured current collectors that perform dual tasks. They serve as both electronic conductors and packaging to prevent water and oxygen from entering the battery.".

According to researchers, the design of this miniature battery also keeps the "atomic highway" of the cathode consistent, allowing lithium ions to quickly and directly pass through the cathode and enter the device. Because ions can pass through the cathode more effectively, they can be made thicker without affecting this critical property, which in turn doubles the amount of energy storage chemicals they can contain.

Ultimately, this results in the energy density of micro batteries being four times higher than current cutting-edge designs. The weight of this miniature battery is the same as two grains of rice, but its energy and power density are 100 times its volume, and researchers believe it can play a role in many fields. These fields include micro flying robots, wearable devices, medical implants that provide longer lifespans, or countless wireless devices that make up the Internet of Things.

Scientists are continuing to study the chemical and physical composition of their new batteries and working to improve their performance.

The study was published in the journal Advanced Materials.

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