Novel micro-battery could power IoT devices

Researchers are developing a micro-battery that is much more efficient at a smaller size

Spotted: As electronics are becoming smaller, one problem designers face is how to get more power out of ever-smaller batteries. This is a particularly difficult problem because energy density becomes exponentially harder to improve as a battery shrinks. One reason for this is that relatively larger portions of the battery need to be used for protective packaging. But what if micro-batteries could incorporate a protective layer as part of the battery? This is the solution that researchers at the University of Pennsylvania’s School of Engineering and Applied Science have come up with. 

The researchers, led by James Pikul, assistant professor in the Department of Mechanical Engineering and Applied Mechanics, developed a new kind of cathode that increased the amount of the battery that could store energy while also acting as a protective shell. This reduces the need for space-taking, non-conductive material that is normally used to protect the chemical components. 

Micro-batteries have tended to use very thin cathodes, made of crushed particles that are compressed to creates a porous structure. The team developed a way to make thicker electrodes that still allowed for fast ion movement. They did this by developing a cathode material that could be “electroplated” directly onto thin metal foils, which also act as the casing. 

Pikul describes the process as aligning, “the cathode’s ‘atomic highways, meaning lithium ions can move via the fastest and most direct routes through the cathode and into the device, improving the micro-battery’s power density while maintaining a high energy density.” In fact, the new micro-batteries have the energy and power density of batteries that are a hundred times larger while only weighing as much as two grains of rice. Pikul adds: “We essentially made current collectors that perform double duty. They act as both an electron conductor and as the packaging that prevents water and oxygen from getting into the battery.” 

It is not only tiny devices that need better batteries. As electric vehicles replace those powered by fossil fuels, efficient, greener batteries are becoming an urgent necessity. At Springwise, we have seen this urgency translated into innovations such as a battery manufacturing process that cuts out the chemicals and a rechargeable battery made from cement. 

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