Battery Packaging Breakthrough Improves Energy Density

Batteries are used in all sorts of devices that we routinely use daily. Rechargeable batteries can be found inside smartphones, tablets, computers, headphones, and all manner of other devices. University of Pennsylvania researchers in the school of engineering and applied science have discovered a breakthrough in building and packaging microbatteries, expanding their energy density while keeping them very small.

Scientists on the project developed a new type of current collector and cathode able to encase parts of the materials storing energy and serve as a protective shell at the same time. The design eliminates the requirement for the battery to have non-conductive packaging normally used to protect chemicals inside of a typical battery. Study lead James Pikul says the researchers made current collectors that double as the packaging for the battery preventing water and oxygen from getting inside.

The breakthrough offers improved space efficiency and provides an energy density four times higher than current state-of-the-art microbatteries. One of the batteries, seen in the image above, is small enough to be placed on the head of a delicate dandelion without causing damage. The battery is also small and lightweight enough to be carried by insects.

In the future, batteries based on the new technology could lead to smaller flying drones, improved implanted medical devices, and new Internet of Things devices currently impossible due to the size of batteries. For the project, scientists developed a new way to construct electrodes allowing them to be thick while simultaneously allowing fast ion and electron transport.

The team deposited the cathode directly from a bath of molten salts providing a major advantage over a conventional cathode. That advantage comes because the new battery design has virtually no porosity or air gaps. The new construction method results in microbatteries offering the energy and power density of batteries that are hundreds of times larger. More energy density means the ability to run more complicated devices for longer time frames.