Flexible, high-performance battery could soon find its way to your smartwatch


May 2, 2014

Rice University postdoctoral researcher Yang Yang holds an energy storage unit with the best qualities of batteries and supercapacitors in a scalable, flexible package (Image: Tour Group/Rice University)

Rice University postdoctoral researcher Yang Yang holds an energy storage unit with the best qualities of batteries and supercapacitors in a scalable, flexible package (Image: Tour Group/Rice University)

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Researchers at Rice University have created an ultra-thin, high-performance flexible battery that is lithium-free, only a hundredth of an inch thick, and also doubles as a supercapacitor. The technology could find use in mobile and wearable electronics such as smartphones and fitness bands.

Smartwatches haven't been around for very long, and yet it is already clear that one of the most limiting factors to their performance (and, ultimately, their usefulness) is battery life. Batteries are generally rigid, bulky and heavy, which is exactly what you don't want to feel on your wrist all day long.

Flexible batteries are an attractive prospect that would lead to better wearable gadgets for consumers. We've seen examples before, but their performance hasn't been up to par when compared to their Li-ion counterparts. Now, researchers at Rice University have come up with a technology that looks very promising.

Rice chemist James Tour and colleagues created high-performance electrodes by etching a 900 nanometer-thick layer of nickel fluoride with regularly spaced holes that were only five nanometers in diameter, increasing surface area for added energy storage. They then enclosed the electrodes in an electrolyte made of potassium hydroxide in polyvinyl alcohol.

According to the scientists, the device behaves like a battery, even though it is structured as a supercapacitor. Indeed, it can be used as both; it can be charged and discharged quickly, like a supercapacitor, or it can be charged with a lower current rate, in which case it will also discharge slowly, behaving like a battery.

The device is only a hundredth of an inch thick and it was found to hold 76 percent of its original capacity after 10,000 charge-discharge cycles and 1,000 bending cycles. Energy density was measured at 384 Wh/kg, and power density at 112 kW/kg.

This technology could be used in wearable, flexible electronics such as the next generation of smartwatches and fitness bands. The scientists say they are already in talks with companies interested in large-scale production, which they say could make the battery even thinner, and also scale it up by either increasing its size or stacking layers on top of one another.

The advance is described in the latest issue of the Journal of the American Chemical Society.

Source: Rice University

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion. All articles by Dario Borghino

Been seeing articles about super batteries for years and years. Not ONE of these batteries has made it to market. Its like graphene, if its so awesome where are the products ? Its all just talk it seems. Wake me up when you have a product to review.

Brian Mcc

Brian Mcc++


I never paid that much attention to battery technologies used today but I noticed when I scanned the GM EV1 Wikipedia entry the other day that they released it with lead acid batteries but planned a NiMH version at the time. With Tesla using Lithium-ion that means electric cars have spanned 3 major battery technologies over the last 20 years. Here are some of the major ones:

lead-acid - Created in 1859. heavy and still used for things like car batteries and solar power storage.

Alkaline Batteries first created in 1899 and still used in most non rechargable household batteries (AAA,AA,C,D etc.)

NiCad was the rechargeable battery of choice before NiMH (and Lithium-ion) replaced it in the 90s

NiMH is still used in the Prius today and cheap rechargeable electronics like cordless phones and radio controlled cars.

Lithium-ion - Commercial introduction in 1991 sales volume picked up in the early 2000's, highest storage density but expensive, used in smart phones and cars like Leaf, Volt, and Tesla.

Batteries don't improve at the pace of the electronics they power but the research hasn't stood still either. Considering even battery powered automobiles are starting to see market traction with Lithium-ion any improvement from here forward is likely to have major global impact. Supercapacitors are behind but the rate they improving is faster than with batteries and they are charge/uncharged faster so there is potential for them to fill a niche along side batteries in the short term.

Part of the inconvenience of short battery life is not just charging them but finding enough continuous time to allow them to charge slowly. Lithium-ion needs several hours to charge but a supercapacitor could basically be charged at a stop light but only supply enough juice for ~30 miles or something. The 2 used in conjunction could improve EV range significantly.


I think that would be great when matched up with a flexible screen and circuit board. It would be a phone that is small and unrolled to make it easier to see and use.

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